On Wednesday, October 19, 2022 at 5:20:24 AM UTC-4, Victor Vasylyev wrote:
> On Wednesday, October 19, 2022 at 12:42:23 AM UTC+3, pete...@gmail.com wrote:
> > On Tuesday, October 18, 2022 at 4:34:06 PM UTC-4, Robert Carnegie wrote:
> > > On Tuesday, 18 October 2022 at 19:53:42 UTC+1, Dimensional Traveler wrote:
> > > > On 10/18/2022 9:11 AM, Paul S Person wrote:
> > > > > On Mon, 17 Oct 2022 12:06:44 -0700, Dimensional Traveler
> > > > > <dtr...@sonic.net> wrote:
> > > > >
> > > > >> On 10/17/2022 8:39 AM, Paul S Person wrote:
> > > > >>> On Sun, 16 Oct 2022 04:36:57 -0700 (PDT), Victor Vasylyev
> > > > >>> <kara...@gmail.com> wrote:
> > > > >>>
> > > > >>>> On Saturday, October 15, 2022 at 11:16:27 PM UTC+3, pete...@gmail.com wrote:
> > > > >>>>> On Saturday, October 15, 2022 at 3:49:39 PM UTC-4, Robert Carnegie wrote:
> > > > >>>>>> On Friday, 14 October 2022 at 17:00:29 UTC+1, Paul S Person wrote:
> > > > >>>>>>> On Fri, 14 Oct 2022 13:43:51 GMT, sc...@slp53.sl.home (Scott Lurndal)
> > > > >>>>>>> wrote:
> > > > >>>>>>>> Quadibloc <jsa...@ecn.ab.ca> writes:
> > > > >>>>>>>>> On Thursday, October 13, 2022 at 10:04:37 AM UTC-6, Paul S Person wrote:
> > > > >>>>>>>>>
> > > > >>>>>>>>>> But it also contained a statement that this might not work if the
> > > > >>>>>>>>>> whole thing was just rubble: nothing to push on!
> > > > >>>>>>>>>
> > > > >>>>>>>>> And that is quite a reasonable argument,
> > > > >>>>>>>>
> > > > >>>>>>>> Is it? What is the effect of the rubble flying off in all
> > > > >>>>>>>> directions on the orbit of the object?
> > > > >>>>>>> If it is /really/ "all directions", it might well net out to ... none
> > > > >>>>>>> at all.
> > > > >>>>>>>
> > > > >>>>>>> An actual space scientist/physicist made the statement, BTW..
> > > > >>>>>> You'd apply a force, or an impulse, that accelerates
> > > > >>>>>> some or all of the mass out of a collision course
> > > > >>>>>> with Earth (if that's what you're attempting), so it
> > > > >>>>>> would be different from the asteroid somehow
> > > > >>>>>> spontaneously exploding but, mathematically as
> > > > >>>>>> a whole, not accelerating.
> > > > >>>>>>
> > > > >>>>>> However, you could fire a space bullet at the
> > > > >>>>>> flying rock heap and see the bullet and some of the
> > > > >>>>>> rocks fly out of the back of the heap, while the
> > > > >>>>>> rest of the asteroid continues in the original course.
> > > > >>>>>> Like cutting the core out of an apple.
> > > > >>>>>>
> > > > >>>>>> So maybe we need to start thinking about wrapping
> > > > >>>>>> the heap in a big net, first. Or use duct tape.
> > > > >>>>> No need. We have proof of concept.
> > > > >>>>>
> > > > >>>>> We *know* that the asteroid had its orbit changed, and
> > > > >>>>> by more than expected.
> > > > >>>>>
> > > > >>>>> The 'flying in all directions' video was taken by a cubesat
> > > > >>>>> trailing behind the DART probe, so yes, it looks symmetrical.
> > > > >>>>>
> > > > >>>>> If you look at a side view, such as that taken by to James
> > > > >>>>> Webb, it's abundantly clear that most of the ejecta went
> > > > >>>>> In one direction:
> > > > >>>>>
> > > > >>>>> https://www.youtube.com/watch?v=P1zukXq4NDc
> > > > >>>>>
> > > > >>>>> Pt
> > > > >>>> It is possible that not the change in the orbit of Dimorphos did play the main role in the observed post-impact features of the mutual asteroid shadowing.
> > > > >>>> This role could be played by an asymmetric and optically dense near-surface "meteoroid cocoon", consisting of its recoiled debris as a part of material ejected into the hemisphere. Therefore, yet it cannot be ruled out that after the dissipation and fallback of this material onto the surface of Dimorphos, its orbit will be partially or almost completely “restored”.
> > > > >>>
> > > > >>> That wouldn't matter ... provided the potential planet-killer missed
> > > > >>> the planet!
> > > > >>>
> > > > >>> Let's keep the eye on the ball here -- this isn't about changing the
> > > > >>> orbit for All Eternity; it is about changing it on it's next pass past
> > > > >>> our planet. So that it misses.
> > > > >>>
> > > > >>> If it comes back on the same path in the future, we can nudge it
> > > > >>> again.
> > > > >>>
> > > > >> Okay, there's some really bad English here. I'm not sure what Victor
> > > > >> Vasylyev was trying to say. Nitpick: If you change an asteroid's orbit
> > > > >> enough to miss a planet (or, frankly, AT ALL) when it was otherwise
> > > > >> going to hit it, you _HAVE_ changed its orbit for all eternity. Now,
> > > > >> that NEW orbit may intersect your planet next time when it wouldn't have
> > > > >> hit it on the next orbit before you nudged it. (At least partially
> > > > >> because it would have smacked into your planet and no longer be around
> > > > >> to have an orbit but details, details. :P ) In that situation ya,
> > > > >> you're going have to slap it around again.
> > > > >
> > > > > A nitpick to your nitpick: the person I was responding to was positing
> > > > > that the orbit might change back as (in effect) the dust settled.
> > > > >
> > > > > My point was that it wouldn't matter, so long as it missed this time.
> > > > >
> > > > > And, clearly, you are correct: it also wouldn't matter if the new
> > > > > orbit was a problem next time.
> > > > I don't see how an object could "revert" to its previous orbit after it
> > > > had been pushed into a new one absent another push.
> > > >
> > > > I also don't think it is possible to have a shell of debris "orbiting"
> > > > around an asteroid. A ring, sure, but not a sphere like shell, because
> > > > different pieces would have to be orbiting at different speeds at the
> > > > same distance from the primary. Which from what I understand of physics
> > > > simply isn't possible.
> > > There is a ton of assorted space junk pieces orbiting
> > > Earth closely in many random directions as I write.
> > > I think we're meant to be imagining a cloud of stuff,
> > > and not a "shell" such as an egg has.
> > >
> > > And I haven't done the calculations, but the quantity of
> > > stuff flying off the little asteroid evidently /has/ been
> > > accelerated, I think.
> > Vlad described his hypothetical shell as 'optically dense', ie, too thick
> > to see through. I don't think that's stable in the long term. I expect
> > it would first settle into a ring, and then into a ridge on the surface, like
> > Iapetus.
> >
> > pt
> Trying to add some clarity to my founded hypothesis...
> Most of abruptly formed asymmetric "cocoon" (consisting not of "dust", but of relatively large fragments - that's why it did not fly off so far! – see again 50+ seconds in https://www.nature.com/articles/d41586-022-03130-8) should have been concentrated on the side of the main component, where its attraction maximally contributed to the rebound of large fragments of the Dimorphos as loosely-bound rubble pile (such its internal structure was known and became evident after the impact). This asymmetry could shift the center of the summarised "albedo spot" (determined owing to eclipses) towards a shorter orbit relative to the mass center of the parent body. As a result, when interpreting, you can get the illusion of a change in the asteroid's orbit instead of its true change. Up to "cocoon" dissipation and/or fallback.

"pete...@gmail.com" <petertrei@gmail.com> writes:
>On Wednesday, October 19, 2022 at 5:20:24 AM UTC-4, Victor Vasylyev wrote:
>> On Wednesday, October 19, 2022 at 12:42:23 AM UTC+3, pete...@gmail.com wr=
>ote:=20

>> Trying to add some clarity to my founded hypothesis...=20
>> Most of abruptly formed asymmetric "cocoon" (consisting not of "dust", bu=
>t of relatively large fragments - that's why it did not fly off so far! =E2=
>=80=93 see again 50+ seconds in https://www.nature.com/articles/d41586-022-=
>03130-8) should have been concentrated on the side of the main component, w=
>here its attraction maximally contributed to the rebound of large fragments=
> of the Dimorphos as loosely-bound rubble pile (such its internal structure=
> was known and became evident after the impact). This asymmetry could shift=
> the center of the summarised "albedo spot" (determined owing to eclipses) =
>towards a shorter orbit relative to the mass center of the parent body. As =
>a result, when interpreting, you can get the illusion of a change in the as=
>teroid's orbit instead of its true change. Up to "cocoon" dissipation and/o=
>r fallback.
>
>Why do you think the change in the orbit is an illusion?
>
>The stated change is not based on short term observation, but over two week=
>s of
>consistent measurements. The methodology was explained at the follow-up NA=
>SA briefing:
>https://youtu.be/tuGMST5vgP4?t=3D1828
>
>All the data is consistent with the probe hitting, and kicking out a large =
>quantity of debris=20
>(now stretched over 1000s of km, and growing), creating a permanent change =
>in Dimorphos' orbit=20
>around Didymous. This data has held up over more than two weeks of observat=
>ions.
>
>I still don't quite understand your hypothesis. But can you give a reason w=
>hy it should be
>considered? What is the evidence supporting it? (Your URL doesn't work).
>
>pt
>

Works for me. The silly 'flowed' format breaks the URL.

https://www.nature.com/articles/d41586-022-03130-8

It's an editorial, entitled:

"Deflecting asteroids is not enough - we need to know when they approach"

On 10/19/2022 7:57 AM, Scott Lurndal wrote:
> "pete...@gmail.com" <petertrei@gmail.com> writes:
>> On Wednesday, October 19, 2022 at 5:20:24 AM UTC-4, Victor Vasylyev wrote:
>>> On Wednesday, October 19, 2022 at 12:42:23 AM UTC+3, pete...@gmail.com wr=
>> ote:=20
>
>>> Trying to add some clarity to my founded hypothesis...=20
>>> Most of abruptly formed asymmetric "cocoon" (consisting not of "dust", bu=
>> t of relatively large fragments - that's why it did not fly off so far! =E2=
>> =80=93 see again 50+ seconds in https://www.nature.com/articles/d41586-022-=
>> 03130-8) should have been concentrated on the side of the main component, w=
>> here its attraction maximally contributed to the rebound of large fragments=
>> of the Dimorphos as loosely-bound rubble pile (such its internal structure=
>> was known and became evident after the impact). This asymmetry could shift=
>> the center of the summarised "albedo spot" (determined owing to eclipses) =
>> towards a shorter orbit relative to the mass center of the parent body. As =
>> a result, when interpreting, you can get the illusion of a change in the as=
>> teroid's orbit instead of its true change. Up to "cocoon" dissipation and/o=
>> r fallback.
>>
>> Why do you think the change in the orbit is an illusion?
>>
>> The stated change is not based on short term observation, but over two week=
>> s of
>> consistent measurements. The methodology was explained at the follow-up NA=
>> SA briefing:
>> https://youtu.be/tuGMST5vgP4?t=3D1828
>>
>> All the data is consistent with the probe hitting, and kicking out a large =
>> quantity of debris=20
>> (now stretched over 1000s of km, and growing), creating a permanent change =
>> in Dimorphos' orbit=20
>> around Didymous. This data has held up over more than two weeks of observat=
>> ions.
>>
>> I still don't quite understand your hypothesis. But can you give a reason w=
>> hy it should be
>> considered? What is the evidence supporting it? (Your URL doesn't work).
>>
>> pt
>>
>
>
> Works for me. The silly 'flowed' format breaks the URL.
>
>
> https://www.nature.com/articles/d41586-022-03130-8
>
> It's an editorial, entitled:
>
> "Deflecting asteroids is not enough - we need to know when they approach"

Well the truth of that title strikes me as obvious since we can't
deflect them or even know we need to if we don't know they are
approaching. That's why NASA has been systematically mapping as many of
the Earth-crossing objects as they can.

--
I've done good in this world. Now I'm tired and just want to be a cranky
dirty old man.

On Tue, 18 Oct 2022 11:53:39 -0700, Dimensional Traveler
<dtravel@sonic.net> wrote:

>On 10/18/2022 9:11 AM, Paul S Person wrote:
>> On Mon, 17 Oct 2022 12:06:44 -0700, Dimensional Traveler
>> <dtravel@sonic.net> wrote:
>>
>>> On 10/17/2022 8:39 AM, Paul S Person wrote:
>>>> On Sun, 16 Oct 2022 04:36:57 -0700 (PDT), Victor Vasylyev
>>>> <karaforn@gmail.com> wrote:
>>>>
>>>>> On Saturday, October 15, 2022 at 11:16:27 PM UTC+3, pete...@gmail.com wrote:
>>>>>> On Saturday, October 15, 2022 at 3:49:39 PM UTC-4, Robert Carnegie wrote:
>>>>>>> On Friday, 14 October 2022 at 17:00:29 UTC+1, Paul S Person wrote:
>>>>>>>> On Fri, 14 Oct 2022 13:43:51 GMT, sc...@slp53.sl.home (Scott Lurndal)
>>>>>>>> wrote:
>>>>>>>>> Quadibloc <jsa...@ecn.ab.ca> writes:
>>>>>>>>>> On Thursday, October 13, 2022 at 10:04:37 AM UTC-6, Paul S Person wrote:
>>>>>>>>>>
>>>>>>>>>>> But it also contained a statement that this might not work if the
>>>>>>>>>>> whole thing was just rubble: nothing to push on!
>>>>>>>>>>
>>>>>>>>>> And that is quite a reasonable argument,
>>>>>>>>>
>>>>>>>>> Is it? What is the effect of the rubble flying off in all
>>>>>>>>> directions on the orbit of the object?
>>>>>>>> If it is /really/ "all directions", it might well net out to ... none
>>>>>>>> at all.
>>>>>>>>
>>>>>>>> An actual space scientist/physicist made the statement, BTW.
>>>>>>> You'd apply a force, or an impulse, that accelerates
>>>>>>> some or all of the mass out of a collision course
>>>>>>> with Earth (if that's what you're attempting), so it
>>>>>>> would be different from the asteroid somehow
>>>>>>> spontaneously exploding but, mathematically as
>>>>>>> a whole, not accelerating.
>>>>>>>
>>>>>>> However, you could fire a space bullet at the
>>>>>>> flying rock heap and see the bullet and some of the
>>>>>>> rocks fly out of the back of the heap, while the
>>>>>>> rest of the asteroid continues in the original course.
>>>>>>> Like cutting the core out of an apple.
>>>>>>>
>>>>>>> So maybe we need to start thinking about wrapping
>>>>>>> the heap in a big net, first. Or use duct tape.
>>>>>> No need. We have proof of concept.
>>>>>>
>>>>>> We *know* that the asteroid had its orbit changed, and
>>>>>> by more than expected.
>>>>>>
>>>>>> The 'flying in all directions' video was taken by a cubesat
>>>>>> trailing behind the DART probe, so yes, it looks symmetrical.
>>>>>>
>>>>>> If you look at a side view, such as that taken by to James
>>>>>> Webb, it's abundantly clear that most of the ejecta went
>>>>>> In one direction:
>>>>>>
>>>>>> https://www.youtube.com/watch?v=P1zukXq4NDc
>>>>>>
>>>>>> Pt
>>>>> It is possible that not the change in the orbit of Dimorphos did play the main role in the observed post-impact features of the mutual asteroid shadowing.
>>>>> This role could be played by an asymmetric and optically dense near-surface "meteoroid cocoon", consisting of its recoiled debris as a part of material ejected into the hemisphere. Therefore, yet it cannot be ruled out that after the dissipation and fallback of this material onto the surface of Dimorphos, its orbit will be partially or almost completely “restored”.
>>>>
>>>> That wouldn't matter ... provided the potential planet-killer missed
>>>> the planet!
>>>>
>>>> Let's keep the eye on the ball here -- this isn't about changing the
>>>> orbit for All Eternity; it is about changing it on it's next pass past
>>>> our planet. So that it misses.
>>>>
>>>> If it comes back on the same path in the future, we can nudge it
>>>> again.
>>>>
>>> Okay, there's some really bad English here. I'm not sure what Victor
>>> Vasylyev was trying to say. Nitpick: If you change an asteroid's orbit
>>> enough to miss a planet (or, frankly, AT ALL) when it was otherwise
>>> going to hit it, you _HAVE_ changed its orbit for all eternity. Now,
>>> that NEW orbit may intersect your planet next time when it wouldn't have
>>> hit it on the next orbit before you nudged it. (At least partially
>>> because it would have smacked into your planet and no longer be around
>>> to have an orbit but details, details. :P ) In that situation ya,
>>> you're going have to slap it around again.
>>
>> A nitpick to your nitpick: the person I was responding to was positing
>> that the orbit might change back as (in effect) the dust settled.
>>
>> My point was that it wouldn't matter, so long as it missed this time.
>>
>> And, clearly, you are correct: it also wouldn't matter if the new
>> orbit was a problem next time.
>
>I don't see how an object could "revert" to its previous orbit after it
>had been pushed into a new one absent another push.

Perhaps you should take it up with the person who made the claim.

Here's a clue: it wasn't me.
--
"In this connexion, unquestionably the most significant
development was the disintegration, under Christian
influence, of classical conceptions of the family and
of family right."

On Wednesday, October 19, 2022 at 10:57:31 AM UTC-4, Scott Lurndal wrote:
> "pete...@gmail.com" <pete...@gmail.com> writes:
> >On Wednesday, October 19, 2022 at 5:20:24 AM UTC-4, Victor Vasylyev wrote:
> >> On Wednesday, October 19, 2022 at 12:42:23 AM UTC+3, pete...@gmail.com wr=
> >ote:=20
>
> >> Trying to add some clarity to my founded hypothesis...=20
> >> Most of abruptly formed asymmetric "cocoon" (consisting not of "dust", bu=
> >t of relatively large fragments - that's why it did not fly off so far! =E2=
> >=80=93 see again 50+ seconds in https://www.nature.com/articles/d41586-022-=
> >03130-8) should have been concentrated on the side of the main component, w=
> >here its attraction maximally contributed to the rebound of large fragments=
> > of the Dimorphos as loosely-bound rubble pile (such its internal structure=
> > was known and became evident after the impact). This asymmetry could shift=
> > the center of the summarised "albedo spot" (determined owing to eclipses) =
> >towards a shorter orbit relative to the mass center of the parent body. As =
> >a result, when interpreting, you can get the illusion of a change in the as=
> >teroid's orbit instead of its true change. Up to "cocoon" dissipation and/o=
> >r fallback.
> >
> >Why do you think the change in the orbit is an illusion?
> >
> >The stated change is not based on short term observation, but over two week=
> >s of
> >consistent measurements. The methodology was explained at the follow-up NA=
> >SA briefing:
> >https://youtu.be/tuGMST5vgP4?t=3D1828
> >
> >All the data is consistent with the probe hitting, and kicking out a large =
> >quantity of debris=20
> >(now stretched over 1000s of km, and growing), creating a permanent change =
> >in Dimorphos' orbit=20
> >around Didymous. This data has held up over more than two weeks of observat=
> >ions.
> >
> >I still don't quite understand your hypothesis. But can you give a reason w=
> >hy it should be
> >considered? What is the evidence supporting it? (Your URL doesn't work).
> >
> >pt
> >
> Works for me. The silly 'flowed' format breaks the URL.
>
>
> https://www.nature.com/articles/d41586-022-03130-8
>
> It's an editorial, entitled:
>
> "Deflecting asteroids is not enough - we need to know when they approach.j

I really don't want to return to the 'formatting' discussion. People should
break lines at 60 characters.

Victor's post implied that there was a video at the URL, and we should
look 50 seconds in. I can't find a video on the page.

pt

On 10/19/2022 9:07 AM, Paul S Person wrote:
> On Tue, 18 Oct 2022 11:53:39 -0700, Dimensional Traveler
> <dtravel@sonic.net> wrote:
>
>> On 10/18/2022 9:11 AM, Paul S Person wrote:
>>> On Mon, 17 Oct 2022 12:06:44 -0700, Dimensional Traveler
>>> <dtravel@sonic.net> wrote:
>>>
>>>> On 10/17/2022 8:39 AM, Paul S Person wrote:
>>>>> On Sun, 16 Oct 2022 04:36:57 -0700 (PDT), Victor Vasylyev
>>>>> <karaforn@gmail.com> wrote:
>>>>>
>>>>>> On Saturday, October 15, 2022 at 11:16:27 PM UTC+3, pete...@gmail.com wrote:
>>>>>>> On Saturday, October 15, 2022 at 3:49:39 PM UTC-4, Robert Carnegie wrote:
>>>>>>>> On Friday, 14 October 2022 at 17:00:29 UTC+1, Paul S Person wrote:
>>>>>>>>> On Fri, 14 Oct 2022 13:43:51 GMT, sc...@slp53.sl.home (Scott Lurndal)
>>>>>>>>> wrote:
>>>>>>>>>> Quadibloc <jsa...@ecn.ab.ca> writes:
>>>>>>>>>>> On Thursday, October 13, 2022 at 10:04:37 AM UTC-6, Paul S Person wrote:
>>>>>>>>>>>
>>>>>>>>>>>> But it also contained a statement that this might not work if the
>>>>>>>>>>>> whole thing was just rubble: nothing to push on!
>>>>>>>>>>>
>>>>>>>>>>> And that is quite a reasonable argument,
>>>>>>>>>>
>>>>>>>>>> Is it? What is the effect of the rubble flying off in all
>>>>>>>>>> directions on the orbit of the object?
>>>>>>>>> If it is /really/ "all directions", it might well net out to ... none
>>>>>>>>> at all.
>>>>>>>>>
>>>>>>>>> An actual space scientist/physicist made the statement, BTW.
>>>>>>>> You'd apply a force, or an impulse, that accelerates
>>>>>>>> some or all of the mass out of a collision course
>>>>>>>> with Earth (if that's what you're attempting), so it
>>>>>>>> would be different from the asteroid somehow
>>>>>>>> spontaneously exploding but, mathematically as
>>>>>>>> a whole, not accelerating.
>>>>>>>>
>>>>>>>> However, you could fire a space bullet at the
>>>>>>>> flying rock heap and see the bullet and some of the
>>>>>>>> rocks fly out of the back of the heap, while the
>>>>>>>> rest of the asteroid continues in the original course.
>>>>>>>> Like cutting the core out of an apple.
>>>>>>>>
>>>>>>>> So maybe we need to start thinking about wrapping
>>>>>>>> the heap in a big net, first. Or use duct tape.
>>>>>>> No need. We have proof of concept.
>>>>>>>
>>>>>>> We *know* that the asteroid had its orbit changed, and
>>>>>>> by more than expected.
>>>>>>>
>>>>>>> The 'flying in all directions' video was taken by a cubesat
>>>>>>> trailing behind the DART probe, so yes, it looks symmetrical.
>>>>>>>
>>>>>>> If you look at a side view, such as that taken by to James
>>>>>>> Webb, it's abundantly clear that most of the ejecta went
>>>>>>> In one direction:
>>>>>>>
>>>>>>> https://www.youtube.com/watch?v=P1zukXq4NDc
>>>>>>>
>>>>>>> Pt
>>>>>> It is possible that not the change in the orbit of Dimorphos did play the main role in the observed post-impact features of the mutual asteroid shadowing.
>>>>>> This role could be played by an asymmetric and optically dense near-surface "meteoroid cocoon", consisting of its recoiled debris as a part of material ejected into the hemisphere. Therefore, yet it cannot be ruled out that after the dissipation and fallback of this material onto the surface of Dimorphos, its orbit will be partially or almost completely “restored”.
>>>>>
>>>>> That wouldn't matter ... provided the potential planet-killer missed
>>>>> the planet!
>>>>>
>>>>> Let's keep the eye on the ball here -- this isn't about changing the
>>>>> orbit for All Eternity; it is about changing it on it's next pass past
>>>>> our planet. So that it misses.
>>>>>
>>>>> If it comes back on the same path in the future, we can nudge it
>>>>> again.
>>>>>
>>>> Okay, there's some really bad English here. I'm not sure what Victor
>>>> Vasylyev was trying to say. Nitpick: If you change an asteroid's orbit
>>>> enough to miss a planet (or, frankly, AT ALL) when it was otherwise
>>>> going to hit it, you _HAVE_ changed its orbit for all eternity. Now,
>>>> that NEW orbit may intersect your planet next time when it wouldn't have
>>>> hit it on the next orbit before you nudged it. (At least partially
>>>> because it would have smacked into your planet and no longer be around
>>>> to have an orbit but details, details. :P ) In that situation ya,
>>>> you're going have to slap it around again.
>>>
>>> A nitpick to your nitpick: the person I was responding to was positing
>>> that the orbit might change back as (in effect) the dust settled.
>>>
>>> My point was that it wouldn't matter, so long as it missed this time.
>>>
>>> And, clearly, you are correct: it also wouldn't matter if the new
>>> orbit was a problem next time.
>>
>> I don't see how an object could "revert" to its previous orbit after it
>> had been pushed into a new one absent another push.
>
> Perhaps you should take it up with the person who made the claim.
>
> Here's a clue: it wasn't me.

Comments weren't aimed at you in particular. Just discussing the
subject, apologies if it seemed personal.

--
I've done good in this world. Now I'm tired and just want to be a cranky
dirty old man.

On Wednesday, October 19, 2022 at 11:10:34 PM UTC+3, Dimensional Traveler wrote:
> On 10/19/2022 9:07 AM, Paul S Person wrote:
> > On Tue, 18 Oct 2022 11:53:39 -0700, Dimensional Traveler
> > <dtr...@sonic.net> wrote:
> >
> >> On 10/18/2022 9:11 AM, Paul S Person wrote:
> >>> On Mon, 17 Oct 2022 12:06:44 -0700, Dimensional Traveler
> >>> <dtr...@sonic.net> wrote:
> >>>
> >>>> On 10/17/2022 8:39 AM, Paul S Person wrote:
> >>>>> On Sun, 16 Oct 2022 04:36:57 -0700 (PDT), Victor Vasylyev
> >>>>> <kara...@gmail.com> wrote:
> >>>>>
> >>>>>> On Saturday, October 15, 2022 at 11:16:27 PM UTC+3, pete...@gmail.com wrote:
> >>>>>>> On Saturday, October 15, 2022 at 3:49:39 PM UTC-4, Robert Carnegie wrote:
> >>>>>>>> On Friday, 14 October 2022 at 17:00:29 UTC+1, Paul S Person wrote:
> >>>>>>>>> On Fri, 14 Oct 2022 13:43:51 GMT, sc...@slp53.sl.home (Scott Lurndal)
> >>>>>>>>> wrote:
> >>>>>>>>>> Quadibloc <jsa...@ecn.ab.ca> writes:
> >>>>>>>>>>> On Thursday, October 13, 2022 at 10:04:37 AM UTC-6, Paul S Person wrote:
> >>>>>>>>>>>
> >>>>>>>>>>>> But it also contained a statement that this might not work if the
> >>>>>>>>>>>> whole thing was just rubble: nothing to push on!
> >>>>>>>>>>>
> >>>>>>>>>>> And that is quite a reasonable argument,
> >>>>>>>>>>
> >>>>>>>>>> Is it? What is the effect of the rubble flying off in all
> >>>>>>>>>> directions on the orbit of the object?
> >>>>>>>>> If it is /really/ "all directions", it might well net out to .... none
> >>>>>>>>> at all.
> >>>>>>>>>
> >>>>>>>>> An actual space scientist/physicist made the statement, BTW.
> >>>>>>>> You'd apply a force, or an impulse, that accelerates
> >>>>>>>> some or all of the mass out of a collision course
> >>>>>>>> with Earth (if that's what you're attempting), so it
> >>>>>>>> would be different from the asteroid somehow
> >>>>>>>> spontaneously exploding but, mathematically as
> >>>>>>>> a whole, not accelerating.
> >>>>>>>>
> >>>>>>>> However, you could fire a space bullet at the
> >>>>>>>> flying rock heap and see the bullet and some of the
> >>>>>>>> rocks fly out of the back of the heap, while the
> >>>>>>>> rest of the asteroid continues in the original course.
> >>>>>>>> Like cutting the core out of an apple.
> >>>>>>>>
> >>>>>>>> So maybe we need to start thinking about wrapping
> >>>>>>>> the heap in a big net, first. Or use duct tape.
> >>>>>>> No need. We have proof of concept.
> >>>>>>>
> >>>>>>> We *know* that the asteroid had its orbit changed, and
> >>>>>>> by more than expected.
> >>>>>>>
> >>>>>>> The 'flying in all directions' video was taken by a cubesat
> >>>>>>> trailing behind the DART probe, so yes, it looks symmetrical.
> >>>>>>>
> >>>>>>> If you look at a side view, such as that taken by to James
> >>>>>>> Webb, it's abundantly clear that most of the ejecta went
> >>>>>>> In one direction:
> >>>>>>>
> >>>>>>> https://www.youtube.com/watch?v=P1zukXq4NDc
> >>>>>>>
> >>>>>>> Pt
> >>>>>> It is possible that not the change in the orbit of Dimorphos did play the main role in the observed post-impact features of the mutual asteroid shadowing.
> >>>>>> This role could be played by an asymmetric and optically dense near-surface "meteoroid cocoon", consisting of its recoiled debris as a part of material ejected into the hemisphere. Therefore, yet it cannot be ruled out that after the dissipation and fallback of this material onto the surface of Dimorphos, its orbit will be partially or almost completely “restored”.
> >>>>>
> >>>>> That wouldn't matter ... provided the potential planet-killer missed
> >>>>> the planet!
> >>>>>
> >>>>> Let's keep the eye on the ball here -- this isn't about changing the
> >>>>> orbit for All Eternity; it is about changing it on it's next pass past
> >>>>> our planet. So that it misses.
> >>>>>
> >>>>> If it comes back on the same path in the future, we can nudge it
> >>>>> again.
> >>>>>
> >>>> Okay, there's some really bad English here. I'm not sure what Victor
> >>>> Vasylyev was trying to say. Nitpick: If you change an asteroid's orbit
> >>>> enough to miss a planet (or, frankly, AT ALL) when it was otherwise
> >>>> going to hit it, you _HAVE_ changed its orbit for all eternity. Now,
> >>>> that NEW orbit may intersect your planet next time when it wouldn't have
> >>>> hit it on the next orbit before you nudged it. (At least partially
> >>>> because it would have smacked into your planet and no longer be around
> >>>> to have an orbit but details, details. :P ) In that situation ya,
> >>>> you're going have to slap it around again.
> >>>
> >>> A nitpick to your nitpick: the person I was responding to was positing
> >>> that the orbit might change back as (in effect) the dust settled.
> >>>
> >>> My point was that it wouldn't matter, so long as it missed this time.
> >>>
> >>> And, clearly, you are correct: it also wouldn't matter if the new
> >>> orbit was a problem next time.
> >>
> >> I don't see how an object could "revert" to its previous orbit after it
> >> had been pushed into a new one absent another push.
> >
> > Perhaps you should take it up with the person who made the claim.
> >
> > Here's a clue: it wasn't me.
> Comments weren't aimed at you in particular. Just discussing the
> subject, apologies if it seemed personal.
> --
> I've done good in this world. Now I'm tired and just want to be a cranky
> dirty old man.
I will give a few specific arguments that could cause the illusion of changing the orbit:
1. The abrupt occurrence of a "meteoroid cocoon" from relatively large fragments of Dimorphos did not lead to their distant expansion. On the previously cited video https://www.youtube.com/watch?v=bfqVqOl9S9w (sorry, an another link was given in the previous post by mistake), you can see that the summarised albedo spot "Dimorphos + сocoon" approximately doubled in about a second in the direction perpendicular to its orbit. During the next 10 seconds, its dimensions practically did not change, in contrast to the ejection dust flow.
2. Measurements of the orbital parameters were, of necessity, made by an indirect method, that is, by the position of the asteroid's shadow. This method is sensitive only to optical quantities (albedo), which in this case did not characterize the position of the center of mass of Dimorrphos.
3. Estimates show that the expansion of the summarised albedo spot "Dimorphos + cocoon" of about half of its asteroid size towards the main component is sufficient to distort the real orbital velocity of the asteroid's center of mass by the value given in the NASA results.
4. During several weeks of measurements, the configuration of the summarised albedo spot, most likely, did not change. Therefore, multiple fixation of the position of the summarised albedo spot "Dimorphos + cocoon" is not an argument in favor of the reality of the interpretation. For final conclusions, more long-term observations are needed - up to "cocoon" dissipation, transformation and/or fallback.
5. Impulse transmission to Dimorphos (exactly as a whole!) is impossible either directly by impact of a small impactor or by material ejection. This follows from the laws of shock wave physics (absolutely inelastic impact) when applied to a loosely-bound rubble pile target.

On Wednesday, October 19, 2022 at 4:55:54 PM UTC-4, Victor Vasylyev wrote:
> On Wednesday, October 19, 2022 at 11:10:34 PM UTC+3, Dimensional Traveler wrote:
> > On 10/19/2022 9:07 AM, Paul S Person wrote:
> > > On Tue, 18 Oct 2022 11:53:39 -0700, Dimensional Traveler
> > > <dtr...@sonic.net> wrote:
> > >
> > >> On 10/18/2022 9:11 AM, Paul S Person wrote:
> > >>> On Mon, 17 Oct 2022 12:06:44 -0700, Dimensional Traveler
> > >>> <dtr...@sonic.net> wrote:
> > >>>
> > >>>> On 10/17/2022 8:39 AM, Paul S Person wrote:
> > >>>>> On Sun, 16 Oct 2022 04:36:57 -0700 (PDT), Victor Vasylyev
> > >>>>> <kara...@gmail.com> wrote:
> > >>>>>
> > >>>>>> On Saturday, October 15, 2022 at 11:16:27 PM UTC+3, pete...@gmail.com wrote:
> > >>>>>>> On Saturday, October 15, 2022 at 3:49:39 PM UTC-4, Robert Carnegie wrote:
> > >>>>>>>> On Friday, 14 October 2022 at 17:00:29 UTC+1, Paul S Person wrote:
> > >>>>>>>>> On Fri, 14 Oct 2022 13:43:51 GMT, sc...@slp53.sl.home (Scott Lurndal)
> > >>>>>>>>> wrote:
> > >>>>>>>>>> Quadibloc <jsa...@ecn.ab.ca> writes:
> > >>>>>>>>>>> On Thursday, October 13, 2022 at 10:04:37 AM UTC-6, Paul S Person wrote:
> > >>>>>>>>>>>
> > >>>>>>>>>>>> But it also contained a statement that this might not work if the
> > >>>>>>>>>>>> whole thing was just rubble: nothing to push on!
> > >>>>>>>>>>>
> > >>>>>>>>>>> And that is quite a reasonable argument,
> > >>>>>>>>>>
> > >>>>>>>>>> Is it? What is the effect of the rubble flying off in all
> > >>>>>>>>>> directions on the orbit of the object?
> > >>>>>>>>> If it is /really/ "all directions", it might well net out to .... none
> > >>>>>>>>> at all.
> > >>>>>>>>>
> > >>>>>>>>> An actual space scientist/physicist made the statement, BTW.
> > >>>>>>>> You'd apply a force, or an impulse, that accelerates
> > >>>>>>>> some or all of the mass out of a collision course
> > >>>>>>>> with Earth (if that's what you're attempting), so it
> > >>>>>>>> would be different from the asteroid somehow
> > >>>>>>>> spontaneously exploding but, mathematically as
> > >>>>>>>> a whole, not accelerating.
> > >>>>>>>>
> > >>>>>>>> However, you could fire a space bullet at the
> > >>>>>>>> flying rock heap and see the bullet and some of the
> > >>>>>>>> rocks fly out of the back of the heap, while the
> > >>>>>>>> rest of the asteroid continues in the original course.
> > >>>>>>>> Like cutting the core out of an apple.
> > >>>>>>>>
> > >>>>>>>> So maybe we need to start thinking about wrapping
> > >>>>>>>> the heap in a big net, first. Or use duct tape.
> > >>>>>>> No need. We have proof of concept.
> > >>>>>>>
> > >>>>>>> We *know* that the asteroid had its orbit changed, and
> > >>>>>>> by more than expected.
> > >>>>>>>
> > >>>>>>> The 'flying in all directions' video was taken by a cubesat
> > >>>>>>> trailing behind the DART probe, so yes, it looks symmetrical.
> > >>>>>>>
> > >>>>>>> If you look at a side view, such as that taken by to James
> > >>>>>>> Webb, it's abundantly clear that most of the ejecta went
> > >>>>>>> In one direction:
> > >>>>>>>
> > >>>>>>> https://www.youtube.com/watch?v=P1zukXq4NDc
> > >>>>>>>
> > >>>>>>> Pt
> > >>>>>> It is possible that not the change in the orbit of Dimorphos did play the main role in the observed post-impact features of the mutual asteroid shadowing.
> > >>>>>> This role could be played by an asymmetric and optically dense near-surface "meteoroid cocoon", consisting of its recoiled debris as a part of material ejected into the hemisphere. Therefore, yet it cannot be ruled out that after the dissipation and fallback of this material onto the surface of Dimorphos, its orbit will be partially or almost completely “restored”.
> > >>>>>
> > >>>>> That wouldn't matter ... provided the potential planet-killer missed
> > >>>>> the planet!
> > >>>>>
> > >>>>> Let's keep the eye on the ball here -- this isn't about changing the
> > >>>>> orbit for All Eternity; it is about changing it on it's next pass past
> > >>>>> our planet. So that it misses.
> > >>>>>
> > >>>>> If it comes back on the same path in the future, we can nudge it
> > >>>>> again.
> > >>>>>
> > >>>> Okay, there's some really bad English here. I'm not sure what Victor
> > >>>> Vasylyev was trying to say. Nitpick: If you change an asteroid's orbit
> > >>>> enough to miss a planet (or, frankly, AT ALL) when it was otherwise
> > >>>> going to hit it, you _HAVE_ changed its orbit for all eternity. Now,
> > >>>> that NEW orbit may intersect your planet next time when it wouldn't have
> > >>>> hit it on the next orbit before you nudged it. (At least partially
> > >>>> because it would have smacked into your planet and no longer be around
> > >>>> to have an orbit but details, details. :P ) In that situation ya,
> > >>>> you're going have to slap it around again.
> > >>>
> > >>> A nitpick to your nitpick: the person I was responding to was positing
> > >>> that the orbit might change back as (in effect) the dust settled.
> > >>>
> > >>> My point was that it wouldn't matter, so long as it missed this time.
> > >>>
> > >>> And, clearly, you are correct: it also wouldn't matter if the new
> > >>> orbit was a problem next time.
> > >>
> > >> I don't see how an object could "revert" to its previous orbit after it
> > >> had been pushed into a new one absent another push.
> > >
> > > Perhaps you should take it up with the person who made the claim.
> > >
> > > Here's a clue: it wasn't me.
> > Comments weren't aimed at you in particular. Just discussing the
> > subject, apologies if it seemed personal.
> > --
> > I've done good in this world. Now I'm tired and just want to be a cranky
> > dirty old man.
> I will give a few specific arguments that could cause the illusion of changing the orbit:
> 1. The abrupt occurrence of a "meteoroid cocoon" from relatively large fragments of Dimorphos did not lead to their distant expansion. On the previously cited video https://www.youtube.com/watch?v=bfqVqOl9S9w (sorry, an another link was given in the previous post by mistake), you can see that the summarised albedo spot "Dimorphos + сocoon" approximately doubled in about a second in the direction perpendicular to its orbit. During the next 10 seconds, its dimensions practically did not change, in contrast to the ejection dust flow.
> 2. Measurements of the orbital parameters were, of necessity, made by an indirect method, that is, by the position of the asteroid's shadow. This method is sensitive only to optical quantities (albedo), which in this case did not characterize the position of the center of mass of Dimorrphos.
> 3. Estimates show that the expansion of the summarised albedo spot "Dimorphos + cocoon" of about half of its asteroid size towards the main component is sufficient to distort the real orbital velocity of the asteroid's center of mass by the value given in the NASA results.
> 4. During several weeks of measurements, the configuration of the summarised albedo spot, most likely, did not change. Therefore, multiple fixation of the position of the summarised albedo spot "Dimorphos + cocoon" is not an argument in favor of the reality of the interpretation. For final conclusions, more long-term observations are needed - up to "cocoon" dissipation, transformation and/or fallback.
> 5. Impulse transmission to Dimorphos (exactly as a whole!) is impossible either directly by impact of a small impactor or by material ejection. This follows from the laws of shock wave physics (absolutely inelastic impact) when applied to a loosely-bound rubble pile target.

On Thursday, October 20, 2022 at 12:29:35 AM UTC+3, pete...@gmail.com wrote:
> On Wednesday, October 19, 2022 at 4:55:54 PM UTC-4, Victor Vasylyev wrote:
> > On Wednesday, October 19, 2022 at 11:10:34 PM UTC+3, Dimensional Traveler wrote:
> > > On 10/19/2022 9:07 AM, Paul S Person wrote:
> > > > On Tue, 18 Oct 2022 11:53:39 -0700, Dimensional Traveler
> > > > <dtr...@sonic.net> wrote:
> > > >
> > > >> On 10/18/2022 9:11 AM, Paul S Person wrote:
> > > >>> On Mon, 17 Oct 2022 12:06:44 -0700, Dimensional Traveler
> > > >>> <dtr...@sonic.net> wrote:
> > > >>>
> > > >>>> On 10/17/2022 8:39 AM, Paul S Person wrote:
> > > >>>>> On Sun, 16 Oct 2022 04:36:57 -0700 (PDT), Victor Vasylyev
> > > >>>>> <kara...@gmail.com> wrote:
> > > >>>>>
> > > >>>>>> On Saturday, October 15, 2022 at 11:16:27 PM UTC+3, pete...@gmail.com wrote:
> > > >>>>>>> On Saturday, October 15, 2022 at 3:49:39 PM UTC-4, Robert Carnegie wrote:
> > > >>>>>>>> On Friday, 14 October 2022 at 17:00:29 UTC+1, Paul S Person wrote:
> > > >>>>>>>>> On Fri, 14 Oct 2022 13:43:51 GMT, sc...@slp53.sl.home (Scott Lurndal)
> > > >>>>>>>>> wrote:
> > > >>>>>>>>>> Quadibloc <jsa...@ecn.ab.ca> writes:
> > > >>>>>>>>>>> On Thursday, October 13, 2022 at 10:04:37 AM UTC-6, Paul S Person wrote:
> > > >>>>>>>>>>>
> > > >>>>>>>>>>>> But it also contained a statement that this might not work if the
> > > >>>>>>>>>>>> whole thing was just rubble: nothing to push on!
> > > >>>>>>>>>>>
> > > >>>>>>>>>>> And that is quite a reasonable argument,
> > > >>>>>>>>>>
> > > >>>>>>>>>> Is it? What is the effect of the rubble flying off in all
> > > >>>>>>>>>> directions on the orbit of the object?
> > > >>>>>>>>> If it is /really/ "all directions", it might well net out to ... none
> > > >>>>>>>>> at all.
> > > >>>>>>>>>
> > > >>>>>>>>> An actual space scientist/physicist made the statement, BTW..
> > > >>>>>>>> You'd apply a force, or an impulse, that accelerates
> > > >>>>>>>> some or all of the mass out of a collision course
> > > >>>>>>>> with Earth (if that's what you're attempting), so it
> > > >>>>>>>> would be different from the asteroid somehow
> > > >>>>>>>> spontaneously exploding but, mathematically as
> > > >>>>>>>> a whole, not accelerating.
> > > >>>>>>>>
> > > >>>>>>>> However, you could fire a space bullet at the
> > > >>>>>>>> flying rock heap and see the bullet and some of the
> > > >>>>>>>> rocks fly out of the back of the heap, while the
> > > >>>>>>>> rest of the asteroid continues in the original course.
> > > >>>>>>>> Like cutting the core out of an apple.
> > > >>>>>>>>
> > > >>>>>>>> So maybe we need to start thinking about wrapping
> > > >>>>>>>> the heap in a big net, first. Or use duct tape.
> > > >>>>>>> No need. We have proof of concept.
> > > >>>>>>>
> > > >>>>>>> We *know* that the asteroid had its orbit changed, and
> > > >>>>>>> by more than expected.
> > > >>>>>>>
> > > >>>>>>> The 'flying in all directions' video was taken by a cubesat
> > > >>>>>>> trailing behind the DART probe, so yes, it looks symmetrical.
> > > >>>>>>>
> > > >>>>>>> If you look at a side view, such as that taken by to James
> > > >>>>>>> Webb, it's abundantly clear that most of the ejecta went
> > > >>>>>>> In one direction:
> > > >>>>>>>
> > > >>>>>>> https://www.youtube.com/watch?v=P1zukXq4NDc
> > > >>>>>>>
> > > >>>>>>> Pt
> > > >>>>>> It is possible that not the change in the orbit of Dimorphos did play the main role in the observed post-impact features of the mutual asteroid shadowing.
> > > >>>>>> This role could be played by an asymmetric and optically dense near-surface "meteoroid cocoon", consisting of its recoiled debris as a part of material ejected into the hemisphere. Therefore, yet it cannot be ruled out that after the dissipation and fallback of this material onto the surface of Dimorphos, its orbit will be partially or almost completely “restored”.
> > > >>>>>
> > > >>>>> That wouldn't matter ... provided the potential planet-killer missed
> > > >>>>> the planet!
> > > >>>>>
> > > >>>>> Let's keep the eye on the ball here -- this isn't about changing the
> > > >>>>> orbit for All Eternity; it is about changing it on it's next pass past
> > > >>>>> our planet. So that it misses.
> > > >>>>>
> > > >>>>> If it comes back on the same path in the future, we can nudge it
> > > >>>>> again.
> > > >>>>>
> > > >>>> Okay, there's some really bad English here. I'm not sure what Victor
> > > >>>> Vasylyev was trying to say. Nitpick: If you change an asteroid's orbit
> > > >>>> enough to miss a planet (or, frankly, AT ALL) when it was otherwise
> > > >>>> going to hit it, you _HAVE_ changed its orbit for all eternity. Now,
> > > >>>> that NEW orbit may intersect your planet next time when it wouldn't have
> > > >>>> hit it on the next orbit before you nudged it. (At least partially
> > > >>>> because it would have smacked into your planet and no longer be around
> > > >>>> to have an orbit but details, details. :P ) In that situation ya,
> > > >>>> you're going have to slap it around again.
> > > >>>
> > > >>> A nitpick to your nitpick: the person I was responding to was positing
> > > >>> that the orbit might change back as (in effect) the dust settled.
> > > >>>
> > > >>> My point was that it wouldn't matter, so long as it missed this time.
> > > >>>
> > > >>> And, clearly, you are correct: it also wouldn't matter if the new
> > > >>> orbit was a problem next time.
> > > >>
> > > >> I don't see how an object could "revert" to its previous orbit after it
> > > >> had been pushed into a new one absent another push.
> > > >
> > > > Perhaps you should take it up with the person who made the claim.
> > > >
> > > > Here's a clue: it wasn't me.
> > > Comments weren't aimed at you in particular. Just discussing the
> > > subject, apologies if it seemed personal.
> > > --
> > > I've done good in this world. Now I'm tired and just want to be a cranky
> > > dirty old man.
> > I will give a few specific arguments that could cause the illusion of changing the orbit:
> > 1. The abrupt occurrence of a "meteoroid cocoon" from relatively large fragments of Dimorphos did not lead to their distant expansion. On the previously cited video https://www.youtube.com/watch?v=bfqVqOl9S9w (sorry, an another link was given in the previous post by mistake), you can see that the summarised albedo spot "Dimorphos + сocoon" approximately doubled in about a second in the direction perpendicular to its orbit. During the next 10 seconds, its dimensions practically did not change, in contrast to the ejection dust flow.
> > 2. Measurements of the orbital parameters were, of necessity, made by an indirect method, that is, by the position of the asteroid's shadow. This method is sensitive only to optical quantities (albedo), which in this case did not characterize the position of the center of mass of Dimorrphos.
> > 3. Estimates show that the expansion of the summarised albedo spot "Dimorphos + cocoon" of about half of its asteroid size towards the main component is sufficient to distort the real orbital velocity of the asteroid's center of mass by the value given in the NASA results.
> > 4. During several weeks of measurements, the configuration of the summarised albedo spot, most likely, did not change. Therefore, multiple fixation of the position of the summarised albedo spot "Dimorphos + cocoon" is not an argument in favor of the reality of the interpretation. For final conclusions, more long-term observations are needed - up to "cocoon" dissipation, transformation and/or fallback.
> > 5. Impulse transmission to Dimorphos (exactly as a whole!) is impossible either directly by impact of a small impactor or by material ejection. This follows from the laws of shock wave physics (absolutely inelastic impact) when applied to a loosely-bound rubble pile target.
> Do you actually understand how occultation timings are used to demonstrate the
> orbit has changed?
>
> I'm sorry, but I'm coming to the conclusion that I can no longer take you seriously.
>
> pt

On Thursday, October 20, 2022 at 7:37:28 AM UTC-4, Victor Vasylyev wrote:
> On Thursday, October 20, 2022 at 12:29:35 AM UTC+3, pete...@gmail.com wrote:
> > On Wednesday, October 19, 2022 at 4:55:54 PM UTC-4, Victor Vasylyev wrote:
> > > On Wednesday, October 19, 2022 at 11:10:34 PM UTC+3, Dimensional Traveler wrote:
> > > > On 10/19/2022 9:07 AM, Paul S Person wrote:
> > > > > On Tue, 18 Oct 2022 11:53:39 -0700, Dimensional Traveler
> > > > > <dtr...@sonic.net> wrote:
> > > > >
> > > > >> On 10/18/2022 9:11 AM, Paul S Person wrote:
> > > > >>> On Mon, 17 Oct 2022 12:06:44 -0700, Dimensional Traveler
> > > > >>> <dtr...@sonic.net> wrote:
> > > > >>>
> > > > >>>> On 10/17/2022 8:39 AM, Paul S Person wrote:
> > > > >>>>> On Sun, 16 Oct 2022 04:36:57 -0700 (PDT), Victor Vasylyev
> > > > >>>>> <kara...@gmail.com> wrote:
> > > > >>>>>
> > > > >>>>>> On Saturday, October 15, 2022 at 11:16:27 PM UTC+3, pete...@gmail.com wrote:
> > > > >>>>>>> On Saturday, October 15, 2022 at 3:49:39 PM UTC-4, Robert Carnegie wrote:
> > > > >>>>>>>> On Friday, 14 October 2022 at 17:00:29 UTC+1, Paul S Person wrote:
> > > > >>>>>>>>> On Fri, 14 Oct 2022 13:43:51 GMT, sc...@slp53.sl.home (Scott Lurndal)
> > > > >>>>>>>>> wrote:
> > > > >>>>>>>>>> Quadibloc <jsa...@ecn.ab.ca> writes:
> > > > >>>>>>>>>>> On Thursday, October 13, 2022 at 10:04:37 AM UTC-6, Paul S Person wrote:
> > > > >>>>>>>>>>>
> > > > >>>>>>>>>>>> But it also contained a statement that this might not work if the
> > > > >>>>>>>>>>>> whole thing was just rubble: nothing to push on!
> > > > >>>>>>>>>>>
> > > > >>>>>>>>>>> And that is quite a reasonable argument,
> > > > >>>>>>>>>>
> > > > >>>>>>>>>> Is it? What is the effect of the rubble flying off in all
> > > > >>>>>>>>>> directions on the orbit of the object?
> > > > >>>>>>>>> If it is /really/ "all directions", it might well net out to ... none
> > > > >>>>>>>>> at all.
> > > > >>>>>>>>>
> > > > >>>>>>>>> An actual space scientist/physicist made the statement, BTW.
> > > > >>>>>>>> You'd apply a force, or an impulse, that accelerates
> > > > >>>>>>>> some or all of the mass out of a collision course
> > > > >>>>>>>> with Earth (if that's what you're attempting), so it
> > > > >>>>>>>> would be different from the asteroid somehow
> > > > >>>>>>>> spontaneously exploding but, mathematically as
> > > > >>>>>>>> a whole, not accelerating.
> > > > >>>>>>>>
> > > > >>>>>>>> However, you could fire a space bullet at the
> > > > >>>>>>>> flying rock heap and see the bullet and some of the
> > > > >>>>>>>> rocks fly out of the back of the heap, while the
> > > > >>>>>>>> rest of the asteroid continues in the original course.
> > > > >>>>>>>> Like cutting the core out of an apple.
> > > > >>>>>>>>
> > > > >>>>>>>> So maybe we need to start thinking about wrapping
> > > > >>>>>>>> the heap in a big net, first. Or use duct tape.
> > > > >>>>>>> No need. We have proof of concept.
> > > > >>>>>>>
> > > > >>>>>>> We *know* that the asteroid had its orbit changed, and
> > > > >>>>>>> by more than expected.
> > > > >>>>>>>
> > > > >>>>>>> The 'flying in all directions' video was taken by a cubesat
> > > > >>>>>>> trailing behind the DART probe, so yes, it looks symmetrical.
> > > > >>>>>>>
> > > > >>>>>>> If you look at a side view, such as that taken by to James
> > > > >>>>>>> Webb, it's abundantly clear that most of the ejecta went
> > > > >>>>>>> In one direction:
> > > > >>>>>>>
> > > > >>>>>>> https://www.youtube.com/watch?v=P1zukXq4NDc
> > > > >>>>>>>
> > > > >>>>>>> Pt
> > > > >>>>>> It is possible that not the change in the orbit of Dimorphos did play the main role in the observed post-impact features of the mutual asteroid shadowing.
> > > > >>>>>> This role could be played by an asymmetric and optically dense near-surface "meteoroid cocoon", consisting of its recoiled debris as a part of material ejected into the hemisphere. Therefore, yet it cannot be ruled out that after the dissipation and fallback of this material onto the surface of Dimorphos, its orbit will be partially or almost completely “restored”.
> > > > >>>>>
> > > > >>>>> That wouldn't matter ... provided the potential planet-killer missed
> > > > >>>>> the planet!
> > > > >>>>>
> > > > >>>>> Let's keep the eye on the ball here -- this isn't about changing the
> > > > >>>>> orbit for All Eternity; it is about changing it on it's next pass past
> > > > >>>>> our planet. So that it misses.
> > > > >>>>>
> > > > >>>>> If it comes back on the same path in the future, we can nudge it
> > > > >>>>> again.
> > > > >>>>>
> > > > >>>> Okay, there's some really bad English here. I'm not sure what Victor
> > > > >>>> Vasylyev was trying to say. Nitpick: If you change an asteroid's orbit
> > > > >>>> enough to miss a planet (or, frankly, AT ALL) when it was otherwise
> > > > >>>> going to hit it, you _HAVE_ changed its orbit for all eternity.. Now,
> > > > >>>> that NEW orbit may intersect your planet next time when it wouldn't have
> > > > >>>> hit it on the next orbit before you nudged it. (At least partially
> > > > >>>> because it would have smacked into your planet and no longer be around
> > > > >>>> to have an orbit but details, details. :P ) In that situation ya,
> > > > >>>> you're going have to slap it around again.
> > > > >>>
> > > > >>> A nitpick to your nitpick: the person I was responding to was positing
> > > > >>> that the orbit might change back as (in effect) the dust settled.
> > > > >>>
> > > > >>> My point was that it wouldn't matter, so long as it missed this time.
> > > > >>>
> > > > >>> And, clearly, you are correct: it also wouldn't matter if the new
> > > > >>> orbit was a problem next time.
> > > > >>
> > > > >> I don't see how an object could "revert" to its previous orbit after it
> > > > >> had been pushed into a new one absent another push.
> > > > >
> > > > > Perhaps you should take it up with the person who made the claim.
> > > > >
> > > > > Here's a clue: it wasn't me.
> > > > Comments weren't aimed at you in particular. Just discussing the
> > > > subject, apologies if it seemed personal.
> > > > --
> > > > I've done good in this world. Now I'm tired and just want to be a cranky
> > > > dirty old man.
> > > I will give a few specific arguments that could cause the illusion of changing the orbit:
> > > 1. The abrupt occurrence of a "meteoroid cocoon" from relatively large fragments of Dimorphos did not lead to their distant expansion. On the previously cited video https://www.youtube.com/watch?v=bfqVqOl9S9w (sorry, an another link was given in the previous post by mistake), you can see that the summarised albedo spot "Dimorphos + сocoon" approximately doubled in about a second in the direction perpendicular to its orbit. During the next 10 seconds, its dimensions practically did not change, in contrast to the ejection dust flow.
> > > 2. Measurements of the orbital parameters were, of necessity, made by an indirect method, that is, by the position of the asteroid's shadow. This method is sensitive only to optical quantities (albedo), which in this case did not characterize the position of the center of mass of Dimorrphos.
> > > 3. Estimates show that the expansion of the summarised albedo spot "Dimorphos + cocoon" of about half of its asteroid size towards the main component is sufficient to distort the real orbital velocity of the asteroid's center of mass by the value given in the NASA results.
> > > 4. During several weeks of measurements, the configuration of the summarised albedo spot, most likely, did not change. Therefore, multiple fixation of the position of the summarised albedo spot "Dimorphos + cocoon" is not an argument in favor of the reality of the interpretation. For final conclusions, more long-term observations are needed - up to "cocoon" dissipation, transformation and/or fallback.
> > > 5. Impulse transmission to Dimorphos (exactly as a whole!) is impossible either directly by impact of a small impactor or by material ejection. This follows from the laws of shock wave physics (absolutely inelastic impact) when applied to a loosely-bound rubble pile target.
> > Do you actually understand how occultation timings are used to demonstrate the
> > orbit has changed?
> >
> > I'm sorry, but I'm coming to the conclusion that I can no longer take you seriously.
> >
> > pt
> It is probably that my hypothesis today does not look convincing enough. Future observations will clarify the situation. But the probability that a PhD in astrophysics with many years of university teaching experience does not understand the method of orbital period, determining from observations of the mutual occultations of binary system components, looks less than the probability of impulse transfer in a perfectly inelastic collision ...
> To complete the discussion, I can recommend my article on improved approach to the to the more effective asteroid deflection:
> https://link.springer.com/article/10.1007%2Fs11038-012-9410-2
> as well as:
> https://en.wikipedia.org/wiki/Asteroid_impact_avoidance#Focused_solar_energy

On Thursday, October 20, 2022 at 10:08:48 AM UTC-4, pete...@gmail.com wrote:
> On Thursday, October 20, 2022 at 7:37:28 AM UTC-4, Victor Vasylyev wrote:
> > On Thursday, October 20, 2022 at 12:29:35 AM UTC+3, pete...@gmail.com wrote:
> > > On Wednesday, October 19, 2022 at 4:55:54 PM UTC-4, Victor Vasylyev wrote:
> > > > On Wednesday, October 19, 2022 at 11:10:34 PM UTC+3, Dimensional Traveler wrote:
> > > > > On 10/19/2022 9:07 AM, Paul S Person wrote:
> > > > > > On Tue, 18 Oct 2022 11:53:39 -0700, Dimensional Traveler
> > > > > > <dtr...@sonic.net> wrote:
> > > > > >
> > > > > >> On 10/18/2022 9:11 AM, Paul S Person wrote:
> > > > > >>> On Mon, 17 Oct 2022 12:06:44 -0700, Dimensional Traveler
> > > > > >>> <dtr...@sonic.net> wrote:
> > > > > >>>
> > > > > >>>> On 10/17/2022 8:39 AM, Paul S Person wrote:
> > > > > >>>>> On Sun, 16 Oct 2022 04:36:57 -0700 (PDT), Victor Vasylyev
> > > > > >>>>> <kara...@gmail.com> wrote:
> > > > > >>>>>
> > > > > >>>>>> On Saturday, October 15, 2022 at 11:16:27 PM UTC+3, pete....@gmail.com wrote:
> > > > > >>>>>>> On Saturday, October 15, 2022 at 3:49:39 PM UTC-4, Robert Carnegie wrote:
> > > > > >>>>>>>> On Friday, 14 October 2022 at 17:00:29 UTC+1, Paul S Person wrote:
> > > > > >>>>>>>>> On Fri, 14 Oct 2022 13:43:51 GMT, sc...@slp53.sl.home (Scott Lurndal)
> > > > > >>>>>>>>> wrote:
> > > > > >>>>>>>>>> Quadibloc <jsa...@ecn.ab.ca> writes:
> > > > > >>>>>>>>>>> On Thursday, October 13, 2022 at 10:04:37 AM UTC-6, Paul S Person wrote:
> > > > > >>>>>>>>>>>
> > > > > >>>>>>>>>>>> But it also contained a statement that this might not work if the
> > > > > >>>>>>>>>>>> whole thing was just rubble: nothing to push on!
> > > > > >>>>>>>>>>>
> > > > > >>>>>>>>>>> And that is quite a reasonable argument,
> > > > > >>>>>>>>>>
> > > > > >>>>>>>>>> Is it? What is the effect of the rubble flying off in all
> > > > > >>>>>>>>>> directions on the orbit of the object?
> > > > > >>>>>>>>> If it is /really/ "all directions", it might well net out to ... none
> > > > > >>>>>>>>> at all.
> > > > > >>>>>>>>>
> > > > > >>>>>>>>> An actual space scientist/physicist made the statement, BTW.
> > > > > >>>>>>>> You'd apply a force, or an impulse, that accelerates
> > > > > >>>>>>>> some or all of the mass out of a collision course
> > > > > >>>>>>>> with Earth (if that's what you're attempting), so it
> > > > > >>>>>>>> would be different from the asteroid somehow
> > > > > >>>>>>>> spontaneously exploding but, mathematically as
> > > > > >>>>>>>> a whole, not accelerating.
> > > > > >>>>>>>>
> > > > > >>>>>>>> However, you could fire a space bullet at the
> > > > > >>>>>>>> flying rock heap and see the bullet and some of the
> > > > > >>>>>>>> rocks fly out of the back of the heap, while the
> > > > > >>>>>>>> rest of the asteroid continues in the original course.
> > > > > >>>>>>>> Like cutting the core out of an apple.
> > > > > >>>>>>>>
> > > > > >>>>>>>> So maybe we need to start thinking about wrapping
> > > > > >>>>>>>> the heap in a big net, first. Or use duct tape.
> > > > > >>>>>>> No need. We have proof of concept.
> > > > > >>>>>>>
> > > > > >>>>>>> We *know* that the asteroid had its orbit changed, and
> > > > > >>>>>>> by more than expected.
> > > > > >>>>>>>
> > > > > >>>>>>> The 'flying in all directions' video was taken by a cubesat
> > > > > >>>>>>> trailing behind the DART probe, so yes, it looks symmetrical.
> > > > > >>>>>>>
> > > > > >>>>>>> If you look at a side view, such as that taken by to James
> > > > > >>>>>>> Webb, it's abundantly clear that most of the ejecta went
> > > > > >>>>>>> In one direction:
> > > > > >>>>>>>
> > > > > >>>>>>> https://www.youtube.com/watch?v=P1zukXq4NDc
> > > > > >>>>>>>
> > > > > >>>>>>> Pt
> > > > > >>>>>> It is possible that not the change in the orbit of Dimorphos did play the main role in the observed post-impact features of the mutual asteroid shadowing.
> > > > > >>>>>> This role could be played by an asymmetric and optically dense near-surface "meteoroid cocoon", consisting of its recoiled debris as a part of material ejected into the hemisphere. Therefore, yet it cannot be ruled out that after the dissipation and fallback of this material onto the surface of Dimorphos, its orbit will be partially or almost completely “restored”.
> > > > > >>>>>
> > > > > >>>>> That wouldn't matter ... provided the potential planet-killer missed
> > > > > >>>>> the planet!
> > > > > >>>>>
> > > > > >>>>> Let's keep the eye on the ball here -- this isn't about changing the
> > > > > >>>>> orbit for All Eternity; it is about changing it on it's next pass past
> > > > > >>>>> our planet. So that it misses.
> > > > > >>>>>
> > > > > >>>>> If it comes back on the same path in the future, we can nudge it
> > > > > >>>>> again.
> > > > > >>>>>
> > > > > >>>> Okay, there's some really bad English here. I'm not sure what Victor
> > > > > >>>> Vasylyev was trying to say. Nitpick: If you change an asteroid's orbit
> > > > > >>>> enough to miss a planet (or, frankly, AT ALL) when it was otherwise
> > > > > >>>> going to hit it, you _HAVE_ changed its orbit for all eternity. Now,
> > > > > >>>> that NEW orbit may intersect your planet next time when it wouldn't have
> > > > > >>>> hit it on the next orbit before you nudged it. (At least partially
> > > > > >>>> because it would have smacked into your planet and no longer be around
> > > > > >>>> to have an orbit but details, details. :P ) In that situation ya,
> > > > > >>>> you're going have to slap it around again.
> > > > > >>>
> > > > > >>> A nitpick to your nitpick: the person I was responding to was positing
> > > > > >>> that the orbit might change back as (in effect) the dust settled.
> > > > > >>>
> > > > > >>> My point was that it wouldn't matter, so long as it missed this time.
> > > > > >>>
> > > > > >>> And, clearly, you are correct: it also wouldn't matter if the new
> > > > > >>> orbit was a problem next time.
> > > > > >>
> > > > > >> I don't see how an object could "revert" to its previous orbit after it
> > > > > >> had been pushed into a new one absent another push.
> > > > > >
> > > > > > Perhaps you should take it up with the person who made the claim.
> > > > > >
> > > > > > Here's a clue: it wasn't me.
> > > > > Comments weren't aimed at you in particular. Just discussing the
> > > > > subject, apologies if it seemed personal.
> > > > > --
> > > > > I've done good in this world. Now I'm tired and just want to be a cranky
> > > > > dirty old man.
> > > > I will give a few specific arguments that could cause the illusion of changing the orbit:
> > > > 1. The abrupt occurrence of a "meteoroid cocoon" from relatively large fragments of Dimorphos did not lead to their distant expansion. On the previously cited video https://www.youtube.com/watch?v=bfqVqOl9S9w (sorry, an another link was given in the previous post by mistake), you can see that the summarised albedo spot "Dimorphos + сocoon" approximately doubled in about a second in the direction perpendicular to its orbit. During the next 10 seconds, its dimensions practically did not change, in contrast to the ejection dust flow.
> > > > 2. Measurements of the orbital parameters were, of necessity, made by an indirect method, that is, by the position of the asteroid's shadow. This method is sensitive only to optical quantities (albedo), which in this case did not characterize the position of the center of mass of Dimorrphos.
> > > > 3. Estimates show that the expansion of the summarised albedo spot "Dimorphos + cocoon" of about half of its asteroid size towards the main component is sufficient to distort the real orbital velocity of the asteroid's center of mass by the value given in the NASA results.
> > > > 4. During several weeks of measurements, the configuration of the summarised albedo spot, most likely, did not change. Therefore, multiple fixation of the position of the summarised albedo spot "Dimorphos + cocoon" is not an argument in favor of the reality of the interpretation. For final conclusions, more long-term observations are needed - up to "cocoon" dissipation, transformation and/or fallback.
> > > > 5. Impulse transmission to Dimorphos (exactly as a whole!) is impossible either directly by impact of a small impactor or by material ejection.. This follows from the laws of shock wave physics (absolutely inelastic impact) when applied to a loosely-bound rubble pile target.
> > > Do you actually understand how occultation timings are used to demonstrate the
> > > orbit has changed?
> > >
> > > I'm sorry, but I'm coming to the conclusion that I can no longer take you seriously.
> > >
> > > pt
> > It is probably that my hypothesis today does not look convincing enough.. Future observations will clarify the situation. But the probability that a PhD in astrophysics with many years of university teaching experience does not understand the method of orbital period, determining from observations of the mutual occultations of binary system components, looks less than the probability of impulse transfer in a perfectly inelastic collision ...
> > To complete the discussion, I can recommend my article on improved approach to the to the more effective asteroid deflection:
> > https://link.springer.com/article/10.1007%2Fs11038-012-9410-2
> > as well as:
> > https://en.wikipedia.org/wiki/Asteroid_impact_avoidance#Focused_solar_energy
> In that case, I'll continue to pay attention. Understand that this newsgroup has, over the years,
> received many posts from people pushing non-scientific fringe theories, much more than actual
> experts.
>
> What predictions can you make for the Didimous/Dimorphos system that would support your
> hypothesis?

On Wednesday, October 19, 2022 at 2:55:54 PM UTC-6, Victor Vasylyev wrote:

> 5. Impulse transmission to Dimorphos (exactly as a whole!) is impossible either directly by impact of a small impactor or by material ejection. This follows from the laws of shock wave physics (absolutely inelastic impact) when applied to a loosely-bound rubble pile target.

If by "impulse", you mean momentum, since momentum is conserved, the difference between inelastic
impact and elastic impact is that the momentum transferred is not _doubled_ by the impactor bouncing
off in the opposite direction. At least for a rigid body.
But we don't have a rigid body, as you note. However, for the DART spacecraft to transfer no
momentum to the asteroid, the requirement would be that its own momentum would be
unchanged by the collision. Which means it would have to go through the asteroid and come
out on the other side. Preferably undamaged.
So I am puzzled by your claims, although it is certainly possible I have misunderstood them.
In the perfectly elastic case, we have the situation where both momentum and energy are
conserved. This constrains the result of a collision, and leads to the toy where a row of metal
balls are suspended from a framework. With inelastic collisions, energy is turned into heat,
but momentum remains strictly conserved. This is simple physics, and while it can have more
complex consequences, more complex physics (i.e. the physics of shock waves) can't come
back and overrule the basic facts upon which it is built.

John Savard

On Friday, October 21, 2022 at 7:15:17 PM UTC+3, Quadibloc wrote:
> On Wednesday, October 19, 2022 at 2:55:54 PM UTC-6, Victor Vasylyev wrote:
>
> > 5. Impulse transmission to Dimorphos (exactly as a whole!) is impossible either directly by impact of a small impactor or by material ejection. This follows from the laws of shock wave physics (absolutely inelastic impact) when applied to a loosely-bound rubble pile target.
> If by "impulse", you mean momentum, since momentum is conserved, the difference between inelastic
> impact and elastic impact is that the momentum transferred is not _doubled_ by the impactor bouncing
> off in the opposite direction. At least for a rigid body.
> But we don't have a rigid body, as you note. However, for the DART spacecraft to transfer no
> momentum to the asteroid, the requirement would be that its own momentum would be
> unchanged by the collision. Which means it would have to go through the asteroid and come
> out on the other side. Preferably undamaged.
> So I am puzzled by your claims, although it is certainly possible I have misunderstood them.
> In the perfectly elastic case, we have the situation where both momentum and energy are
> conserved. This constrains the result of a collision, and leads to the toy where a row of metal
> balls are suspended from a framework. With inelastic collisions, energy is turned into heat,
> but momentum remains strictly conserved. This is simple physics, and while it can have more
> complex consequences, more complex physics (i.e. the physics of shock waves) can't come
> back and overrule the basic facts upon which it is built.
>
> John Savard

To transfer the momentum from a small impactor (as well as from the accompanying ejection of material) to a big target as a whole, the arising shock wave must pass to the opposite boundary, be reflected with repolarization, and return to the impact zone with some damping. But for target like loose piles of gravel filled by rocks and dust, this is basically impossible. Since the shock wave will die out much earlier due to dissipation in the huge local transition zones of complex-shaped solid fragments with vacuum or dust cavities. Therefore, in fact, all the kinetic energy during the impact turns into heating and position redistribution of the fragments, which are closest to the impact zone. Wherein the momentum is of course conserved.

On Friday, October 21, 2022 at 2:45:44 PM UTC-4, Victor Vasylyev wrote:
> On Friday, October 21, 2022 at 7:15:17 PM UTC+3, Quadibloc wrote:
> > On Wednesday, October 19, 2022 at 2:55:54 PM UTC-6, Victor Vasylyev wrote:
> >
> > > 5. Impulse transmission to Dimorphos (exactly as a whole!) is impossible either directly by impact of a small impactor or by material ejection. This follows from the laws of shock wave physics (absolutely inelastic impact) when applied to a loosely-bound rubble pile target.
> > If by "impulse", you mean momentum, since momentum is conserved, the difference between inelastic
> > impact and elastic impact is that the momentum transferred is not _doubled_ by the impactor bouncing
> > off in the opposite direction. At least for a rigid body.
> > But we don't have a rigid body, as you note. However, for the DART spacecraft to transfer no
> > momentum to the asteroid, the requirement would be that its own momentum would be
> > unchanged by the collision. Which means it would have to go through the asteroid and come
> > out on the other side. Preferably undamaged.
> > So I am puzzled by your claims, although it is certainly possible I have misunderstood them.
> > In the perfectly elastic case, we have the situation where both momentum and energy are
> > conserved. This constrains the result of a collision, and leads to the toy where a row of metal
> > balls are suspended from a framework. With inelastic collisions, energy is turned into heat,
> > but momentum remains strictly conserved. This is simple physics, and while it can have more
> > complex consequences, more complex physics (i.e. the physics of shock waves) can't come
> > back and overrule the basic facts upon which it is built.
> >
> > John Savard
> To transfer the momentum from a small impactor (as well as from the accompanying ejection of material) to a big target as a whole, the arising shock wave must pass to the opposite boundary, be reflected with repolarization, and return to the impact zone with some damping. But for target like loose piles of gravel filled by rocks and dust, this is basically impossible. Since the shock wave will die out much earlier due to dissipation in the huge local transition zones of complex-shaped solid fragments with vacuum or dust cavities. Therefore, in fact, all the kinetic energy during the impact turns into heating and position redistribution of the fragments, which are closest to the impact zone. Wherein the momentum is of course conserved.

You've said that repeatedly. I believe I understand your argument.

Yet the observational data, both of timings of dips in the light curve, and direct observation
of Didymous and Dimorpos by radar, are in agreement that the orbit was shortened by the
impact, and it remains shortened weeks later.

In science, when observation and theory are in conflict, observation wins. The onus is
on you to explain the observations in a way consistent with your theory.

Did you watch the video I linked above? You only need to watch 5-6 minutes.
https://www.youtube.com/watch?v=tuGMST5vgP4&t=1828s

Pt

On Friday, October 21, 2022 at 2:45:44 PM UTC-4, Victor Vasylyev wrote:
> On Friday, October 21, 2022 at 7:15:17 PM UTC+3, Quadibloc wrote:
> > On Wednesday, October 19, 2022 at 2:55:54 PM UTC-6, Victor Vasylyev wrote:
> >
> > > 5. Impulse transmission to Dimorphos (exactly as a whole!) is impossible either directly by impact of a small impactor or by material ejection. This follows from the laws of shock wave physics (absolutely inelastic impact) when applied to a loosely-bound rubble pile target.
> > If by "impulse", you mean momentum, since momentum is conserved, the difference between inelastic
> > impact and elastic impact is that the momentum transferred is not _doubled_ by the impactor bouncing
> > off in the opposite direction. At least for a rigid body.
> > But we don't have a rigid body, as you note. However, for the DART spacecraft to transfer no
> > momentum to the asteroid, the requirement would be that its own momentum would be
> > unchanged by the collision. Which means it would have to go through the asteroid and come
> > out on the other side. Preferably undamaged.
> > So I am puzzled by your claims, although it is certainly possible I have misunderstood them.
> > In the perfectly elastic case, we have the situation where both momentum and energy are
> > conserved. This constrains the result of a collision, and leads to the toy where a row of metal
> > balls are suspended from a framework. With inelastic collisions, energy is turned into heat,
> > but momentum remains strictly conserved. This is simple physics, and while it can have more
> > complex consequences, more complex physics (i.e. the physics of shock waves) can't come
> > back and overrule the basic facts upon which it is built.
> >
> > John Savard
> To transfer the momentum from a small impactor (as well as from the accompanying ejection of material) to a big target as a whole, the arising shock wave must pass to the opposite boundary, be reflected with repolarization, and return to the impact zone with some damping. But for target like loose piles of gravel filled by rocks and dust, this is basically impossible. Since the shock wave will die out much earlier due to dissipation in the huge local transition zones of complex-shaped solid fragments with vacuum or dust cavities. Therefore, in fact, all the kinetic energy during the impact turns into heating and position redistribution of the fragments, which are closest to the impact zone. Wherein the momentum is of course conserved.

To add to my other response, I suggest you consider other mechanisms that
could create a back jet of debris. The impact was the equivalent of several tons of TNT
The impactor was in no way streamlined, dense, or hardened, and traveling at >6 kps.
It is going to push stuff out of the way, hard. The jostling of fragments against each other
will certainly result in many being ejected to the rear, and Dimorphos' miniscule escape
velocity (< 10 cm/s) means most will never return.

Pt

In article <6c9747c9-6a5d-496d-821c-fe0892572459n@googlegroups.com>,
pete...@gmail.com <petertrei@gmail.com> wrote:
>On Friday, October 21, 2022 at 2:45:44 PM UTC-4, Victor Vasylyev wrote:
>> On Friday, October 21, 2022 at 7:15:17 PM UTC+3, Quadibloc wrote:
>> > On Wednesday, October 19, 2022 at 2:55:54 PM UTC-6, Victor Vasylyev wrote:
>> >
>> > > 5. Impulse transmission to Dimorphos (exactly as a whole!) is
>impossible either directly by impact of a small impactor or by material
>ejection. This follows from the laws of shock wave physics (absolutely
>inelastic impact) when applied to a loosely-bound rubble pile target.
>> > If by "impulse", you mean momentum, since momentum is conserved, the
>difference between inelastic
>> > impact and elastic impact is that the momentum transferred is not
>_doubled_ by the impactor bouncing
>> > off in the opposite direction. At least for a rigid body.
>> > But we don't have a rigid body, as you note. However, for the DART
>spacecraft to transfer no
>> > momentum to the asteroid, the requirement would be that its own
>momentum would be
>> > unchanged by the collision. Which means it would have to go through
>the asteroid and come
>> > out on the other side. Preferably undamaged.
>> > So I am puzzled by your claims, although it is certainly possible I
>have misunderstood them.
>> > In the perfectly elastic case, we have the situation where both
>momentum and energy are
>> > conserved. This constrains the result of a collision, and leads to
>the toy where a row of metal
>> > balls are suspended from a framework. With inelastic collisions,
>energy is turned into heat,
>> > but momentum remains strictly conserved. This is simple physics, and
>while it can have more
>> > complex consequences, more complex physics (i.e. the physics of
>shock waves) can't come
>> > back and overrule the basic facts upon which it is built.
>> >
>> > John Savard
>> To transfer the momentum from a small impactor (as well as from the
>accompanying ejection of material) to a big target as a whole, the
>arising shock wave must pass to the opposite boundary, be reflected with
>repolarization, and return to the impact zone with some damping. But for
>target like loose piles of gravel filled by rocks and dust, this is
>basically impossible. Since the shock wave will die out much earlier due
>to dissipation in the huge local transition zones of complex-shaped
>solid fragments with vacuum or dust cavities. Therefore, in fact, all
>the kinetic energy during the impact turns into heating and position
>redistribution of the fragments, which are closest to the impact zone.
>Wherein the momentum is of course conserved.
>
>To add to my other response, I suggest you consider other mechanisms that
>could create a back jet of debris. The impact was the equivalent of
>several tons of TNT
>The impactor was in no way streamlined, dense, or hardened, and
>traveling at >6 kps.
>It is going to push stuff out of the way, hard. The jostling of
>fragments against each other
>will certainly result in many being ejected to the rear, and Dimorphos'
>miniscule escape
> velocity (< 10 cm/s) means most will never return.

(Hal Heydt)
Has anyone managed to determine the materials in the ejected jet?
Is it possible that there are volatile ices under the exposed
surface that would have been vaporized from the heat of impact
and increased the effective thrust from resulting ejected
material?

On Saturday, October 22, 2022 at 8:22:05 AM UTC+3, Dorothy J Heydt wrote:
> In article <6c9747c9-6a5d-496d...@googlegroups.com>,
> pete...@gmail.com <pete...@gmail.com> wrote:
> >On Friday, October 21, 2022 at 2:45:44 PM UTC-4, Victor Vasylyev wrote:
> >> On Friday, October 21, 2022 at 7:15:17 PM UTC+3, Quadibloc wrote:
> >> > On Wednesday, October 19, 2022 at 2:55:54 PM UTC-6, Victor Vasylyev wrote:
> >> >
> >> > > 5. Impulse transmission to Dimorphos (exactly as a whole!) is
> >impossible either directly by impact of a small impactor or by material
> >ejection. This follows from the laws of shock wave physics (absolutely
> >inelastic impact) when applied to a loosely-bound rubble pile target.
> >> > If by "impulse", you mean momentum, since momentum is conserved, the
> >difference between inelastic
> >> > impact and elastic impact is that the momentum transferred is not
> >_doubled_ by the impactor bouncing
> >> > off in the opposite direction. At least for a rigid body.
> >> > But we don't have a rigid body, as you note. However, for the DART
> >spacecraft to transfer no
> >> > momentum to the asteroid, the requirement would be that its own
> >momentum would be
> >> > unchanged by the collision. Which means it would have to go through
> >the asteroid and come
> >> > out on the other side. Preferably undamaged.
> >> > So I am puzzled by your claims, although it is certainly possible I
> >have misunderstood them.
> >> > In the perfectly elastic case, we have the situation where both
> >momentum and energy are
> >> > conserved. This constrains the result of a collision, and leads to
> >the toy where a row of metal
> >> > balls are suspended from a framework. With inelastic collisions,
> >energy is turned into heat,
> >> > but momentum remains strictly conserved. This is simple physics, and
> >while it can have more
> >> > complex consequences, more complex physics (i.e. the physics of
> >shock waves) can't come
> >> > back and overrule the basic facts upon which it is built.
> >> >
> >> > John Savard
> >> To transfer the momentum from a small impactor (as well as from the
> >accompanying ejection of material) to a big target as a whole, the
> >arising shock wave must pass to the opposite boundary, be reflected with
> >repolarization, and return to the impact zone with some damping. But for
> >target like loose piles of gravel filled by rocks and dust, this is
> >basically impossible. Since the shock wave will die out much earlier due
> >to dissipation in the huge local transition zones of complex-shaped
> >solid fragments with vacuum or dust cavities. Therefore, in fact, all
> >the kinetic energy during the impact turns into heating and position
> >redistribution of the fragments, which are closest to the impact zone.
> >Wherein the momentum is of course conserved.
> >
> >To add to my other response, I suggest you consider other mechanisms that
> >could create a back jet of debris. The impact was the equivalent of
> >several tons of TNT
> >The impactor was in no way streamlined, dense, or hardened, and
> >traveling at >6 kps.
> >It is going to push stuff out of the way, hard. The jostling of
> >fragments against each other
> >will certainly result in many being ejected to the rear, and Dimorphos'
> >miniscule escape
> > velocity (< 10 cm/s) means most will never return.
> (Hal Heydt)
> Has anyone managed to determine the materials in the ejected jet?
> Is it possible that there are volatile ices under the exposed
> surface that would have been vaporized from the heat of impact
> and increased the effective thrust from resulting ejected
> material?

Of course, I carefully watched the NASA briefing, as well as everything that has been published on this topic. The information contained there does not negate the fact that the transfer of momentum at a given impact was impossible, in accordance with the physics of shock waves (see post above). Therefore, there is a need for an alternative interpretation of indirect observations of the position of Dimorphos, a variant of which I proposed.
I repeat that observations (both eclipsing and radar) recorded not the center of mass of Dimorphos, but the position of an asymmetrical spot-cocoon (total mass) created by both the asteroid and its near-surface ejected fragments. During the first weeks, this spot was dynamic, hiding the true position of the center of mass. This situation is similar to squid which distract attacking predators by ejecting a cloud of ink, giving themselves an opportunity to temporarily hide your actual location. So, there is no need to draw final conclusions yet, but wait for the dissipation, transformation and/or fallback of summarised cocoon.

On Saturday, October 22, 2022 at 5:42:33 AM UTC-4, Victor Vasylyev wrote:
> On Saturday, October 22, 2022 at 8:22:05 AM UTC+3, Dorothy J Heydt wrote:
> > In article <6c9747c9-6a5d-496d...@googlegroups.com>,
> > pete...@gmail.com <pete...@gmail.com> wrote:
> > >On Friday, October 21, 2022 at 2:45:44 PM UTC-4, Victor Vasylyev wrote:
> > >> On Friday, October 21, 2022 at 7:15:17 PM UTC+3, Quadibloc wrote:
> > >> > On Wednesday, October 19, 2022 at 2:55:54 PM UTC-6, Victor Vasylyev wrote:
> > >> >
> > >> > > 5. Impulse transmission to Dimorphos (exactly as a whole!) is
> > >impossible either directly by impact of a small impactor or by material
> > >ejection. This follows from the laws of shock wave physics (absolutely
> > >inelastic impact) when applied to a loosely-bound rubble pile target.
> > >> > If by "impulse", you mean momentum, since momentum is conserved, the
> > >difference between inelastic
> > >> > impact and elastic impact is that the momentum transferred is not
> > >_doubled_ by the impactor bouncing
> > >> > off in the opposite direction. At least for a rigid body.
> > >> > But we don't have a rigid body, as you note. However, for the DART
> > >spacecraft to transfer no
> > >> > momentum to the asteroid, the requirement would be that its own
> > >momentum would be
> > >> > unchanged by the collision. Which means it would have to go through
> > >the asteroid and come
> > >> > out on the other side. Preferably undamaged.
> > >> > So I am puzzled by your claims, although it is certainly possible I
> > >have misunderstood them.
> > >> > In the perfectly elastic case, we have the situation where both
> > >momentum and energy are
> > >> > conserved. This constrains the result of a collision, and leads to
> > >the toy where a row of metal
> > >> > balls are suspended from a framework. With inelastic collisions,
> > >energy is turned into heat,
> > >> > but momentum remains strictly conserved. This is simple physics, and
> > >while it can have more
> > >> > complex consequences, more complex physics (i.e. the physics of
> > >shock waves) can't come
> > >> > back and overrule the basic facts upon which it is built.
> > >> >
> > >> > John Savard
> > >> To transfer the momentum from a small impactor (as well as from the
> > >accompanying ejection of material) to a big target as a whole, the
> > >arising shock wave must pass to the opposite boundary, be reflected with
> > >repolarization, and return to the impact zone with some damping. But for
> > >target like loose piles of gravel filled by rocks and dust, this is
> > >basically impossible. Since the shock wave will die out much earlier due
> > >to dissipation in the huge local transition zones of complex-shaped
> > >solid fragments with vacuum or dust cavities. Therefore, in fact, all
> > >the kinetic energy during the impact turns into heating and position
> > >redistribution of the fragments, which are closest to the impact zone.
> > >Wherein the momentum is of course conserved.
> > >
> > >To add to my other response, I suggest you consider other mechanisms that
> > >could create a back jet of debris. The impact was the equivalent of
> > >several tons of TNT
> > >The impactor was in no way streamlined, dense, or hardened, and
> > >traveling at >6 kps.
> > >It is going to push stuff out of the way, hard. The jostling of
> > >fragments against each other
> > >will certainly result in many being ejected to the rear, and Dimorphos'
> > >miniscule escape
> > > velocity (< 10 cm/s) means most will never return.
> > (Hal Heydt)
> > Has anyone managed to determine the materials in the ejected jet?
> > Is it possible that there are volatile ices under the exposed
> > surface that would have been vaporized from the heat of impact
> > and increased the effective thrust from resulting ejected
> > material?
> Of course, I carefully watched the NASA briefing, as well as everything that has been published on this topic. The information contained there does not negate the fact that the transfer of momentum at a given impact was impossible, in accordance with the physics of shock waves (see post above). Therefore, there is a need for an alternative interpretation of indirect observations of the position of Dimorphos, a variant of which I proposed.
> I repeat that observations (both eclipsing and radar) recorded not the center of mass of Dimorphos, but the position of an asymmetrical spot-cocoon (total mass) created by both the asteroid and its near-surface ejected fragments. During the first weeks, this spot was dynamic, hiding the true position of the center of mass. This situation is similar to squid which distract attacking predators by ejecting a cloud of ink, giving themselves an opportunity to temporarily hide your actual location. So, there is no need to draw final conclusions yet, but wait for the dissipation, transformation and/or fallback of summarised cocoon.

I don't find it plausible that an 'asymmetrical spot cocoon' from a 160 meter object can create a
radar Illusion that it's on the opposite side of Didymous than it would be if the impact
had not occurred.

Nor do I find it plausible that this cocoon can explain the changed timing of the dips
in the light curve.

How long should we wait?

Pt

On Fri, 21 Oct 2022 19:50:11 -0700 (PDT), "pete...@gmail.com"
<petertrei@gmail.com> wrote:

>On Friday, October 21, 2022 at 2:45:44 PM UTC-4, Victor Vasylyev wrote:
>> On Friday, October 21, 2022 at 7:15:17 PM UTC+3, Quadibloc wrote:
>> > On Wednesday, October 19, 2022 at 2:55:54 PM UTC-6, Victor Vasylyev wrote:
>> >
>> > > 5. Impulse transmission to Dimorphos (exactly as a whole!) is impossible either directly by impact of a small impactor or by material ejection. This follows from the laws of shock wave physics (absolutely inelastic impact) when applied to a loosely-bound rubble pile target.
>> > If by "impulse", you mean momentum, since momentum is conserved, the difference between inelastic
>> > impact and elastic impact is that the momentum transferred is not _doubled_ by the impactor bouncing
>> > off in the opposite direction. At least for a rigid body.
>> > But we don't have a rigid body, as you note. However, for the DART spacecraft to transfer no
>> > momentum to the asteroid, the requirement would be that its own momentum would be
>> > unchanged by the collision. Which means it would have to go through the asteroid and come
>> > out on the other side. Preferably undamaged.
>> > So I am puzzled by your claims, although it is certainly possible I have misunderstood them.
>> > In the perfectly elastic case, we have the situation where both momentum and energy are
>> > conserved. This constrains the result of a collision, and leads to the toy where a row of metal
>> > balls are suspended from a framework. With inelastic collisions, energy is turned into heat,
>> > but momentum remains strictly conserved. This is simple physics, and while it can have more
>> > complex consequences, more complex physics (i.e. the physics of shock waves) can't come
>> > back and overrule the basic facts upon which it is built.
>> >
>> > John Savard
>> To transfer the momentum from a small impactor (as well as from the accompanying ejection of material) to a big target as a whole, the arising shock wave must pass to the opposite boundary, be reflected with repolarization, and return to the impact zone with some damping. But for target like loose piles of gravel filled by rocks and dust, this is basically impossible. Since the shock wave will die out much earlier due to dissipation in the huge local transition zones of complex-shaped solid fragments with vacuum or dust cavities. Therefore, in fact, all the kinetic energy during the impact turns into heating and position redistribution of the fragments, which are closest to the impact zone. Wherein the momentum is of course conserved.
>
>You've said that repeatedly. I believe I understand your argument.
>
>Yet the observational data, both of timings of dips in the light curve, and direct observation
>of Didymous and Dimorpos by radar, are in agreement that the orbit was shortened by the
>impact, and it remains shortened weeks later.
>
>In science, when observation and theory are in conflict, observation wins. The onus is
>on you to explain the observations in a way consistent with your theory.

I was going to say something about his statement, but then I realized
that that statement, itself, doesn't actually /say/ that he believes
the target to be a "loose pile of gravel".

The argument, itself, would seem to rule that out, given the observed
results.

But what do I know? I am not an astrophysicist. Then again, this guy
is (apparently) not part of the team evaluating the mission, and so
may not have all the data. Perhaps he should offer his services to
them.

And he doesn't seem to have ever explained why it /matters/ if the
nudged object resumes its orbit /if in the meantime it misses the
Earth/. Changing the orbit permanently is not the point of the
exercise; changing it enough (and long enough) to miss the Earth is.

Which, since there are a lot of space rocks out there with
(apparently) varying degrees of solidity, makes the ability to change
the orbit of /this/ one a "proof of concept" success. Even if it
eventually changes back.

And I don't want to hear about how it won't change back. I really
don't care if it does or not. The ability to get a large rock (however
dense or undense) heading to our planet to miss is all I am interested
in.

>Did you watch the video I linked above? You only need to watch 5-6 minutes.
>https://www.youtube.com/watch?v=tuGMST5vgP4&t=1828s
--
"In this connexion, unquestionably the most significant
development was the disintegration, under Christian
influence, of classical conceptions of the family and
of family right."

On Sat, 22 Oct 2022 02:42:31 -0700 (PDT), Victor Vasylyev
<karaforn@gmail.com> wrote:

>On Saturday, October 22, 2022 at 8:22:05 AM UTC+3, Dorothy J Heydt wrote:
>> In article <6c9747c9-6a5d-496d...@googlegroups.com>,
>> pete...@gmail.com <pete...@gmail.com> wrote:
>> >On Friday, October 21, 2022 at 2:45:44 PM UTC-4, Victor Vasylyev wrote:
>> >> On Friday, October 21, 2022 at 7:15:17 PM UTC+3, Quadibloc wrote:
>> >> > On Wednesday, October 19, 2022 at 2:55:54 PM UTC-6, Victor Vasylyev wrote:
>> >> >
>> >> > > 5. Impulse transmission to Dimorphos (exactly as a whole!) is
>> >impossible either directly by impact of a small impactor or by material
>> >ejection. This follows from the laws of shock wave physics (absolutely
>> >inelastic impact) when applied to a loosely-bound rubble pile target.
>> >> > If by "impulse", you mean momentum, since momentum is conserved, the
>> >difference between inelastic
>> >> > impact and elastic impact is that the momentum transferred is not
>> >_doubled_ by the impactor bouncing
>> >> > off in the opposite direction. At least for a rigid body.
>> >> > But we don't have a rigid body, as you note. However, for the DART
>> >spacecraft to transfer no
>> >> > momentum to the asteroid, the requirement would be that its own
>> >momentum would be
>> >> > unchanged by the collision. Which means it would have to go through
>> >the asteroid and come
>> >> > out on the other side. Preferably undamaged.
>> >> > So I am puzzled by your claims, although it is certainly possible I
>> >have misunderstood them.
>> >> > In the perfectly elastic case, we have the situation where both
>> >momentum and energy are
>> >> > conserved. This constrains the result of a collision, and leads to
>> >the toy where a row of metal
>> >> > balls are suspended from a framework. With inelastic collisions,
>> >energy is turned into heat,
>> >> > but momentum remains strictly conserved. This is simple physics, and
>> >while it can have more
>> >> > complex consequences, more complex physics (i.e. the physics of
>> >shock waves) can't come
>> >> > back and overrule the basic facts upon which it is built.
>> >> >
>> >> > John Savard
>> >> To transfer the momentum from a small impactor (as well as from the
>> >accompanying ejection of material) to a big target as a whole, the
>> >arising shock wave must pass to the opposite boundary, be reflected with
>> >repolarization, and return to the impact zone with some damping. But for
>> >target like loose piles of gravel filled by rocks and dust, this is
>> >basically impossible. Since the shock wave will die out much earlier due
>> >to dissipation in the huge local transition zones of complex-shaped
>> >solid fragments with vacuum or dust cavities. Therefore, in fact, all
>> >the kinetic energy during the impact turns into heating and position
>> >redistribution of the fragments, which are closest to the impact zone.
>> >Wherein the momentum is of course conserved.
>> >
>> >To add to my other response, I suggest you consider other mechanisms that
>> >could create a back jet of debris. The impact was the equivalent of
>> >several tons of TNT
>> >The impactor was in no way streamlined, dense, or hardened, and
>> >traveling at >6 kps.
>> >It is going to push stuff out of the way, hard. The jostling of
>> >fragments against each other
>> >will certainly result in many being ejected to the rear, and Dimorphos'
>> >miniscule escape
>> > velocity (< 10 cm/s) means most will never return.
>> (Hal Heydt)
>> Has anyone managed to determine the materials in the ejected jet?
>> Is it possible that there are volatile ices under the exposed
>> surface that would have been vaporized from the heat of impact
>> and increased the effective thrust from resulting ejected
>> material?
>
>
>Of course, I carefully watched the NASA briefing, as well as everything that has been published on this topic. The information contained there does not negate the fact that the transfer of momentum at a given impact was impossible, in accordance with the physics of shock waves (see post above). Therefore, there is a need for an alternative interpretation of indirect observations of the position of Dimorphos, a variant of which I proposed.
>I repeat that observations (both eclipsing and radar) recorded not the center of mass of Dimorphos, but the position of an asymmetrical spot-cocoon (total mass) created by both the asteroid and its near-surface ejected fragments. During the first weeks, this spot was dynamic, hiding the true position of the center of mass. This situation is similar to squid which distract attacking predators by ejecting a cloud of ink, giving themselves an opportunity to temporarily hide your actual location. So, there is no need to draw final conclusions yet, but wait for the dissipation, transformation and/or fallback of summarised cocoon.

This sounds a lot like saying that the observed facts don't agree with
your theory, so they must be something else.
--
"In this connexion, unquestionably the most significant
development was the disintegration, under Christian
influence, of classical conceptions of the family and
of family right."

On Saturday, 22 October 2022 at 17:04:27 UTC+1, Paul S Person wrote:
> On Fri, 21 Oct 2022 19:50:11 -0700 (PDT), "pete...@gmail.com"
> <pete...@gmail.com> wrote:
>
> >On Friday, October 21, 2022 at 2:45:44 PM UTC-4, Victor Vasylyev wrote:
> >> On Friday, October 21, 2022 at 7:15:17 PM UTC+3, Quadibloc wrote:
> >> > On Wednesday, October 19, 2022 at 2:55:54 PM UTC-6, Victor Vasylyev wrote:
> >> >
> >> > > 5. Impulse transmission to Dimorphos (exactly as a whole!) is impossible either directly by impact of a small impactor or by material ejection. This follows from the laws of shock wave physics (absolutely inelastic impact) when applied to a loosely-bound rubble pile target.
> >> > If by "impulse", you mean momentum, since momentum is conserved, the difference between inelastic
> >> > impact and elastic impact is that the momentum transferred is not _doubled_ by the impactor bouncing
> >> > off in the opposite direction. At least for a rigid body.
> >> > But we don't have a rigid body, as you note. However, for the DART spacecraft to transfer no
> >> > momentum to the asteroid, the requirement would be that its own momentum would be
> >> > unchanged by the collision. Which means it would have to go through the asteroid and come
> >> > out on the other side. Preferably undamaged.
> >> > So I am puzzled by your claims, although it is certainly possible I have misunderstood them.
> >> > In the perfectly elastic case, we have the situation where both momentum and energy are
> >> > conserved. This constrains the result of a collision, and leads to the toy where a row of metal
> >> > balls are suspended from a framework. With inelastic collisions, energy is turned into heat,
> >> > but momentum remains strictly conserved. This is simple physics, and while it can have more
> >> > complex consequences, more complex physics (i.e. the physics of shock waves) can't come
> >> > back and overrule the basic facts upon which it is built.
> >> >
> >> > John Savard
> >> To transfer the momentum from a small impactor (as well as from the accompanying ejection of material) to a big target as a whole, the arising shock wave must pass to the opposite boundary, be reflected with repolarization, and return to the impact zone with some damping. But for target like loose piles of gravel filled by rocks and dust, this is basically impossible. Since the shock wave will die out much earlier due to dissipation in the huge local transition zones of complex-shaped solid fragments with vacuum or dust cavities. Therefore, in fact, all the kinetic energy during the impact turns into heating and position redistribution of the fragments, which are closest to the impact zone. Wherein the momentum is of course conserved.
> >
> >You've said that repeatedly. I believe I understand your argument.
> >
> >Yet the observational data, both of timings of dips in the light curve, and direct observation
> >of Didymous and Dimorpos by radar, are in agreement that the orbit was shortened by the
> >impact, and it remains shortened weeks later.
> >
> >In science, when observation and theory are in conflict, observation wins. The onus is
> >on you to explain the observations in a way consistent with your theory.
> I was going to say something about his statement, but then I realized
> that that statement, itself, doesn't actually /say/ that he believes
> the target to be a "loose pile of gravel".
>
> The argument, itself, would seem to rule that out, given the observed
> results.
>
> But what do I know? I am not an astrophysicist. Then again, this guy
> is (apparently) not part of the team evaluating the mission, and so
> may not have all the data. Perhaps he should offer his services to
> them.
>
> And he doesn't seem to have ever explained why it /matters/ if the
> nudged object resumes its orbit /if in the meantime it misses the
> Earth/. Changing the orbit permanently is not the point of the
> exercise; changing it enough (and long enough) to miss the Earth is.
>
> Which, since there are a lot of space rocks out there with
> (apparently) varying degrees of solidity, makes the ability to change
> the orbit of /this/ one a "proof of concept" success. Even if it
> eventually changes back.
>
> And I don't want to hear about how it won't change back. I really
> don't care if it does or not. The ability to get a large rock (however
> dense or undense) heading to our planet to miss is all I am interested
> in.

Earth is over 12,500 km wide and it has gravity,
so you want a really good miss. And you don't
want to have to /keep/ pushing it away each time.
What if it comes when Donald Trump is President
and he thinks he can wave it away with a Sharpie?

Having said that... After you convert the expected
impact to a near miss... the thing goes away, and then,
because of orbital mechanics, it comes back. So maybe
you have to deal with it again for that reason.

Robert Carnegie <rja.carnegie@excite.com> writes:
>On Saturday, 22 October 2022 at 17:04:27 UTC+1, Paul S Person wrote:
>> On Fri, 21 Oct 2022 19:50:11 -0700 (PDT), "pete...@gmail.com"=20
>> <pete...@gmail.com> wrote:=20
>>=20

>>=20
>> And I don't want to hear about how it won't change back. I really=20
>> don't care if it does or not. The ability to get a large rock (however=20
>> dense or undense) heading to our planet to miss is all I am interested=20
>> in.
>
>Earth is over 12,500 km wide and it has gravity,
>so you want a really good miss.

It is also moving at 30km/s. A very small (on astronomical
scales) target moving very fast; one does not need to alter
the velocity (or velocity vector) of a potentially intersecting
object by very much to effect a miss.

On Sat, 22 Oct 2022 11:52:51 -0700 (PDT), Robert Carnegie
<rja.carnegie@excite.com> wrote:

>On Saturday, 22 October 2022 at 17:04:27 UTC+1, Paul S Person wrote:
>> On Fri, 21 Oct 2022 19:50:11 -0700 (PDT), "pete...@gmail.com"
>> <pete...@gmail.com> wrote:
>>
>> >On Friday, October 21, 2022 at 2:45:44 PM UTC-4, Victor Vasylyev wrote:
>> >> On Friday, October 21, 2022 at 7:15:17 PM UTC+3, Quadibloc wrote:
>> >> > On Wednesday, October 19, 2022 at 2:55:54 PM UTC-6, Victor Vasylyev wrote:
>> >> >
>> >> > > 5. Impulse transmission to Dimorphos (exactly as a whole!) is impossible either directly by impact of a small impactor or by material ejection. This follows from the laws of shock wave physics (absolutely inelastic impact) when applied to a loosely-bound rubble pile target.
>> >> > If by "impulse", you mean momentum, since momentum is conserved, the difference between inelastic
>> >> > impact and elastic impact is that the momentum transferred is not _doubled_ by the impactor bouncing
>> >> > off in the opposite direction. At least for a rigid body.
>> >> > But we don't have a rigid body, as you note. However, for the DART spacecraft to transfer no
>> >> > momentum to the asteroid, the requirement would be that its own momentum would be
>> >> > unchanged by the collision. Which means it would have to go through the asteroid and come
>> >> > out on the other side. Preferably undamaged.
>> >> > So I am puzzled by your claims, although it is certainly possible I have misunderstood them.
>> >> > In the perfectly elastic case, we have the situation where both momentum and energy are
>> >> > conserved. This constrains the result of a collision, and leads to the toy where a row of metal
>> >> > balls are suspended from a framework. With inelastic collisions, energy is turned into heat,
>> >> > but momentum remains strictly conserved. This is simple physics, and while it can have more
>> >> > complex consequences, more complex physics (i.e. the physics of shock waves) can't come
>> >> > back and overrule the basic facts upon which it is built.
>> >> >
>> >> > John Savard
>> >> To transfer the momentum from a small impactor (as well as from the accompanying ejection of material) to a big target as a whole, the arising shock wave must pass to the opposite boundary, be reflected with repolarization, and return to the impact zone with some damping. But for target like loose piles of gravel filled by rocks and dust, this is basically impossible. Since the shock wave will die out much earlier due to dissipation in the huge local transition zones of complex-shaped solid fragments with vacuum or dust cavities. Therefore, in fact, all the kinetic energy during the impact turns into heating and position redistribution of the fragments, which are closest to the impact zone. Wherein the momentum is of course conserved.
>> >
>> >You've said that repeatedly. I believe I understand your argument.
>> >
>> >Yet the observational data, both of timings of dips in the light curve, and direct observation
>> >of Didymous and Dimorpos by radar, are in agreement that the orbit was shortened by the
>> >impact, and it remains shortened weeks later.
>> >
>> >In science, when observation and theory are in conflict, observation wins. The onus is
>> >on you to explain the observations in a way consistent with your theory.
>> I was going to say something about his statement, but then I realized
>> that that statement, itself, doesn't actually /say/ that he believes
>> the target to be a "loose pile of gravel".
>>
>> The argument, itself, would seem to rule that out, given the observed
>> results.
>>
>> But what do I know? I am not an astrophysicist. Then again, this guy
>> is (apparently) not part of the team evaluating the mission, and so
>> may not have all the data. Perhaps he should offer his services to
>> them.
>>
>> And he doesn't seem to have ever explained why it /matters/ if the
>> nudged object resumes its orbit /if in the meantime it misses the
>> Earth/. Changing the orbit permanently is not the point of the
>> exercise; changing it enough (and long enough) to miss the Earth is.
>>
>> Which, since there are a lot of space rocks out there with
>> (apparently) varying degrees of solidity, makes the ability to change
>> the orbit of /this/ one a "proof of concept" success. Even if it
>> eventually changes back.
>>
>> And I don't want to hear about how it won't change back. I really
>> don't care if it does or not. The ability to get a large rock (however
>> dense or undense) heading to our planet to miss is all I am interested
>> in.
>
>Earth is over 12,500 km wide and it has gravity,
>so you want a really good miss. And you don't
>want to have to /keep/ pushing it away each time.
>What if it comes when Donald Trump is President
>and he thinks he can wave it away with a Sharpie?

As to that hurricane path map, I agree that Trump's Sharpie was a very
dumb idea.

Nonetheless, if you find it online and examine it closely, you will
see that the sharpie expanded the expected possible path of the
hurricane into the next State.

That doesn't sound too unreasonable. What else would you expect it to
do when it reached the border on the map but keep on going into the
next State? Teleport to Winipeg? Stop on a dime?

The /real/ problem, as I recall understanding it at the time, was that
the map he was using was an /old/ map, the implication being that a
more recent map would not have had those possible paths on it but
rather a path closer to the path actually taken.

The underlying problem, of course, was/is that he is Donald Trump. Who
appears to be having a very hard time adjusting to the realities of
life, now that they have come to call on him.
--
"In this connexion, unquestionably the most significant
development was the disintegration, under Christian
influence, of classical conceptions of the family and
of family right."

On Saturday, October 22, 2022 at 5:42:33 AM UTC-4, Victor Vasylyev wrote:
> On Saturday, October 22, 2022 at 8:22:05 AM UTC+3, Dorothy J Heydt wrote:
> > In article <6c9747c9-6a5d-496d...@googlegroups.com>,
> > pete...@gmail.com <pete...@gmail.com> wrote:
> > >On Friday, October 21, 2022 at 2:45:44 PM UTC-4, Victor Vasylyev wrote:
> > >> On Friday, October 21, 2022 at 7:15:17 PM UTC+3, Quadibloc wrote:
> > >> > On Wednesday, October 19, 2022 at 2:55:54 PM UTC-6, Victor Vasylyev wrote:
> > >> >
> > >> > > 5. Impulse transmission to Dimorphos (exactly as a whole!) is
> > >impossible either directly by impact of a small impactor or by material
> > >ejection. This follows from the laws of shock wave physics (absolutely
> > >inelastic impact) when applied to a loosely-bound rubble pile target.
> > >> > If by "impulse", you mean momentum, since momentum is conserved, the
> > >difference between inelastic
> > >> > impact and elastic impact is that the momentum transferred is not
> > >_doubled_ by the impactor bouncing
> > >> > off in the opposite direction. At least for a rigid body.
> > >> > But we don't have a rigid body, as you note. However, for the DART
> > >spacecraft to transfer no
> > >> > momentum to the asteroid, the requirement would be that its own
> > >momentum would be
> > >> > unchanged by the collision. Which means it would have to go through
> > >the asteroid and come
> > >> > out on the other side. Preferably undamaged.
> > >> > So I am puzzled by your claims, although it is certainly possible I
> > >have misunderstood them.
> > >> > In the perfectly elastic case, we have the situation where both
> > >momentum and energy are
> > >> > conserved. This constrains the result of a collision, and leads to
> > >the toy where a row of metal
> > >> > balls are suspended from a framework. With inelastic collisions,
> > >energy is turned into heat,
> > >> > but momentum remains strictly conserved. This is simple physics, and
> > >while it can have more
> > >> > complex consequences, more complex physics (i.e. the physics of
> > >shock waves) can't come
> > >> > back and overrule the basic facts upon which it is built.
> > >> >
> > >> > John Savard
> > >> To transfer the momentum from a small impactor (as well as from the
> > >accompanying ejection of material) to a big target as a whole, the
> > >arising shock wave must pass to the opposite boundary, be reflected with
> > >repolarization, and return to the impact zone with some damping. But for
> > >target like loose piles of gravel filled by rocks and dust, this is
> > >basically impossible. Since the shock wave will die out much earlier due
> > >to dissipation in the huge local transition zones of complex-shaped
> > >solid fragments with vacuum or dust cavities. Therefore, in fact, all
> > >the kinetic energy during the impact turns into heating and position
> > >redistribution of the fragments, which are closest to the impact zone.
> > >Wherein the momentum is of course conserved.
> > >
> > >To add to my other response, I suggest you consider other mechanisms that
> > >could create a back jet of debris. The impact was the equivalent of
> > >several tons of TNT
> > >The impactor was in no way streamlined, dense, or hardened, and
> > >traveling at >6 kps.
> > >It is going to push stuff out of the way, hard. The jostling of
> > >fragments against each other
> > >will certainly result in many being ejected to the rear, and Dimorphos'
> > >miniscule escape
> > > velocity (< 10 cm/s) means most will never return.
> > (Hal Heydt)
> > Has anyone managed to determine the materials in the ejected jet?
> > Is it possible that there are volatile ices under the exposed
> > surface that would have been vaporized from the heat of impact
> > and increased the effective thrust from resulting ejected
> > material?
> Of course, I carefully watched the NASA briefing, as well as everything that has been published on this topic. The information contained there does not negate the fact that the transfer of momentum at a given impact was impossible, in accordance with the physics of shock waves (see post above). Therefore, there is a need for an alternative interpretation of indirect observations of the position of Dimorphos, a variant of which I proposed.
> I repeat that observations (both eclipsing and radar) recorded not the center of mass of Dimorphos, but the position of an asymmetrical spot-cocoon (total mass) created by both the asteroid and its near-surface ejected fragments. During the first weeks, this spot was dynamic, hiding the true position of the center of mass. This situation is similar to squid which distract attacking predators by ejecting a cloud of ink, giving themselves an opportunity to temporarily hide your actual location. So, there is no need to draw final conclusions yet, but wait for the dissipation, transformation and/or fallback of summarised cocoon.

I wonder if the problem is that you're assuming the shock wave has to traverse the entire width of
Dimorphos before reflecting back. The asteroid seems to be made of many fragments, which are
not bound together. This makes it difficult for a shockwave to propagate from one fragment to
another, which means that a lot of energy is reflected back at the edge of each fragment. That may
be what allows a jet of debris even in loosely bound "dust bunny"

Pt

On Sunday, October 23, 2022 at 9:41:42 AM UTC-6, Paul S Person wrote:
> On Sat, 22 Oct 2022 11:52:51 -0700 (PDT), Robert Carnegie
> <rja.ca...@excite.com> wrote:

> >Earth is over 12,500 km wide and it has gravity,
> >so you want a really good miss. And you don't
> >want to have to /keep/ pushing it away each time.
> >What if it comes when Donald Trump is President
> >and he thinks he can wave it away with a Sharpie?

> As to that hurricane path map, I agree that Trump's Sharpie was a very
> dumb idea.
>
> Nonetheless, if you find it online and examine it closely, you will
> see that the sharpie expanded the expected possible path of the
> hurricane into the next State.
>
> That doesn't sound too unreasonable. What else would you expect it to
> do when it reached the border on the map but keep on going into the
> next State? Teleport to Winipeg? Stop on a dime?
>
> The /real/ problem, as I recall understanding it at the time, was that
> the map he was using was an /old/ map, the implication being that a
> more recent map would not have had those possible paths on it but
> rather a path closer to the path actually taken.

This doesn't correspond to what I remember from what I saw at the
time, but my memory has been faulty before.

I know that I joked at the time that if his map inspired more people
to *pray* about the hurricane, then the additional power of all
those prayers might have averted disaster!

John Savard