https://www.space.com/universe-three-dimensional-donut?utm_source=Selligent&utm_medium=email&utm_campaign=20210721_SDC_Newsletter_Adhoc&utm_content=20210721_SDC_Newsletter_Adhoc+&utm_term=3175915&m_i=he35HP3dN9r%2BbbLWDvlRILuFPVGk5Pk5wtOvd_k0TBg7ne5MOXAFi8kMZY%2BgF9ohf4vOMa7%2BjoiP9nVYcCrmUSkcLVLf75Bthv&lrh=035e553a0a93d2128307d9417c97e4cc12a02e3fc84d6a4a40a08a0d089a7741&M_BT=5043708734676

On Tuesday, July 27, 2021 at 12:31:06 PM UTC-6, kellehe...@gmail.com wrote:

> " Cylinders are geometrically flat."
>
> Goodness me!.
>
> I am shocked because I am no longer shocked.

They just kind of phrased it wrong. You can roll up a flat piece of paper into
a cylindrical tube without having to stretch or tear it.

That is what they meant. They just declined to use the technical term,
a developable surface.

As in this paragraph:

"Many common map projections are either azimuthal, cylindrical, or
conic. That is because the cylinder and the cone are developable
surfaces, which may be rolled into the plane without stretching or
tearing. Because the surface of the sphere is not a developable
surface, all projections of the Earth on to flat paper, unlike the globe,
have errors in shape, or area, or both."

Of course a cylinder is curved and not flat; they meant something else
which they didn't say properly.

John Savard

On Tuesday, July 27, 2021 at 11:02:23 AM UTC-7, Mike Collins wrote:
> https://www.space.com/universe-three-dimensional-donut?utm_source=Selligent&utm_medium=email&utm_campaign=20210721_SDC_Newsletter_Adhoc&utm_content=20210721_SDC_Newsletter_Adhoc+&utm_term=3175915&m_i=he35HP3dN9r%2BbbLWDvlRILuFPVGk5Pk5wtOvd_k0TBg7ne5MOXAFi8kMZY%2BgF9ohf4vOMa7%2BjoiP9nVYcCrmUSkcLVLf75Bthv&lrh=035e553a0a93d2128307d9417c97e4cc12a02e3fc84d6a4a40a08a0d089a7741&M_BT=5043708734676

No!
It's a pancake!

On Thursday, July 29, 2021 at 7:23:51 AM UTC+1, StarDust wrote:
> On Tuesday, July 27, 2021 at 11:02:23 AM UTC-7, Mike Collins wrote:
> > https://www.space.com/universe-three-dimensional-donut?utm_source=Selligent&utm_medium=email&utm_campaign=20210721_SDC_Newsletter_Adhoc&utm_content=20210721_SDC_Newsletter_Adhoc+&utm_term=3175915&m_i=he35HP3dN9r%2BbbLWDvlRILuFPVGk5Pk5wtOvd_k0TBg7ne5MOXAFi8kMZY%2BgF9ohf4vOMa7%2BjoiP9nVYcCrmUSkcLVLf75Bthv&lrh=035e553a0a93d2128307d9417c97e4cc12a02e3fc84d6a4a40a08a0d089a7741&M_BT=5043708734676
> No!
> It's a pancake!

Good for you StarDust.

The English boys and that section of their society never got the joke they created-

" There are stars everywhere, so that the density of matter, although very variable in detail, is nevertheless on the average everywhere the same. In other words: However far we might travel through space, we should find everywhere an attenuated swarm of fixed stars of approximately the same kind and density.

This view is not in harmony with the theory of Newton. The latter theory rather requires that the universe should have a kind of centre in which the density of the stars is a maximum, and that as we proceed outwards from this centre the group-density of the stars should diminish, until finally, at great distances, it is succeeded by an infinite region of emptiness. The stellar universe ought to be a finite island in the infinite ocean of space.

This conception is in itself not very satisfactory. It is still less satisfactory because it leads to the result that the light emitted by the stars and also individual stars of the stellar system are perpetually passing out into infinite space, never to return, and without ever again coming into interaction with other objects of nature. Such a finite material universe would be destined to become gradually but systematically impoverished." Albert Einstein

https://www.bartleby.com/173/30.html

For sheer entertainment value there is little to beat such fun, after all, rejecting stellar islands (galaxies) while giving the reason for 'warping' space is delightful in a comical sort of way. This is what happens when a 19th century science fantasy novel (itself built on the 17th century and Victorian misadventures with timekeeping) became formalised in the early 20th century.

As you were gentlemen.

On Wednesday, July 28, 2021 at 11:58:29 PM UTC-7, kellehe...@gmail.com wrote:
> On Thursday, July 29, 2021 at 7:23:51 AM UTC+1, StarDust wrote:
> > On Tuesday, July 27, 2021 at 11:02:23 AM UTC-7, Mike Collins wrote:
> > > https://www.space.com/universe-three-dimensional-donut?utm_source=Selligent&utm_medium=email&utm_campaign=20210721_SDC_Newsletter_Adhoc&utm_content=20210721_SDC_Newsletter_Adhoc+&utm_term=3175915&m_i=he35HP3dN9r%2BbbLWDvlRILuFPVGk5Pk5wtOvd_k0TBg7ne5MOXAFi8kMZY%2BgF9ohf4vOMa7%2BjoiP9nVYcCrmUSkcLVLf75Bthv&lrh=035e553a0a93d2128307d9417c97e4cc12a02e3fc84d6a4a40a08a0d089a7741&M_BT=5043708734676
> > No!
> > It's a pancake!
> Good for you StarDust.
>
> The English boys and that section of their society never got the joke they created-
>
> " There are stars everywhere, so that the density of matter, although very variable in detail, is nevertheless on the average everywhere the same. In other words: However far we might travel through space, we should find everywhere an attenuated swarm of fixed stars of approximately the same kind and density.
>
> This view is not in harmony with the theory of Newton. The latter theory rather requires that the universe should have a kind of centre in which the density of the stars is a maximum, and that as we proceed outwards from this centre the group-density of the stars should diminish, until finally, at great distances, it is succeeded by an infinite region of emptiness. The stellar universe ought to be a finite island in the infinite ocean of space.
>
> This conception is in itself not very satisfactory. It is still less satisfactory because it leads to the result that the light emitted by the stars and also individual stars of the stellar system are perpetually passing out into infinite space, never to return, and without ever again coming into interaction with other objects of nature. Such a finite material universe would be destined to become gradually but systematically impoverished." Albert Einstein
>
> https://www.bartleby.com/173/30.html
>
> For sheer entertainment value there is little to beat such fun, after all, rejecting stellar islands (galaxies) while giving the reason for 'warping' space is delightful in a comical sort of way. This is what happens when a 19th century science fantasy novel (itself built on the 17th century and Victorian misadventures with timekeeping) became formalised in the early 20th century.
>
> As you were gentlemen.

I like pancakes!
That's my universe!

On Thursday, July 29, 2021 at 8:27:07 AM UTC+1, StarDust wrote:
> On Wednesday, July 28, 2021 at 11:58:29 PM UTC-7, kellehe...@gmail.com wrote:
> > On Thursday, July 29, 2021 at 7:23:51 AM UTC+1, StarDust wrote:
> > > On Tuesday, July 27, 2021 at 11:02:23 AM UTC-7, Mike Collins wrote:
> > > > https://www.space.com/universe-three-dimensional-donut?utm_source=Selligent&utm_medium=email&utm_campaign=20210721_SDC_Newsletter_Adhoc&utm_content=20210721_SDC_Newsletter_Adhoc+&utm_term=3175915&m_i=he35HP3dN9r%2BbbLWDvlRILuFPVGk5Pk5wtOvd_k0TBg7ne5MOXAFi8kMZY%2BgF9ohf4vOMa7%2BjoiP9nVYcCrmUSkcLVLf75Bthv&lrh=035e553a0a93d2128307d9417c97e4cc12a02e3fc84d6a4a40a08a0d089a7741&M_BT=5043708734676
> > > No!
> > > It's a pancake!
> > Good for you StarDust.
> >
> > The English boys and that section of their society never got the joke they created-
> >
> > " There are stars everywhere, so that the density of matter, although very variable in detail, is nevertheless on the average everywhere the same. In other words: However far we might travel through space, we should find everywhere an attenuated swarm of fixed stars of approximately the same kind and density.
> >
> > This view is not in harmony with the theory of Newton. The latter theory rather requires that the universe should have a kind of centre in which the density of the stars is a maximum, and that as we proceed outwards from this centre the group-density of the stars should diminish, until finally, at great distances, it is succeeded by an infinite region of emptiness. The stellar universe ought to be a finite island in the infinite ocean of space.
> >
> > This conception is in itself not very satisfactory. It is still less satisfactory because it leads to the result that the light emitted by the stars and also individual stars of the stellar system are perpetually passing out into infinite space, never to return, and without ever again coming into interaction with other objects of nature. Such a finite material universe would be destined to become gradually but systematically impoverished." Albert Einstein
> >
> > https://www.bartleby.com/173/30.html
> >
> > For sheer entertainment value there is little to beat such fun, after all, rejecting stellar islands (galaxies) while giving the reason for 'warping' space is delightful in a comical sort of way. This is what happens when a 19th century science fantasy novel (itself built on the 17th century and Victorian misadventures with timekeeping) became formalised in the early 20th century.
> >
> > As you were gentlemen.
> I like pancakes!
> That's my universe!

Mr StarDust, that is as good an answer as any.

On Tuesday, July 27, 2021 at 2:02:23 PM UTC-4, Mike Collins wrote:
> https://www.space.com/universe-three-dimensional-donut?utm_source=Selligent&utm_medium=email&utm_campaign=20210721_SDC_Newsletter_Adhoc&utm_content=20210721_SDC_Newsletter_Adhoc+&utm_term=3175915&m_i=he35HP3dN9r%2BbbLWDvlRILuFPVGk5Pk5wtOvd_k0TBg7ne5MOXAFi8kMZY%2BgF9ohf4vOMa7%2BjoiP9nVYcCrmUSkcLVLf75Bthv&lrh=035e553a0a93d2128307d9417c97e4cc12a02e3fc84d6a4a40a08a0d089a7741&M_BT=5043708734676
>
>

No, it's a coffee mug.

On Thursday, July 29, 2021 at 8:37:03 AM UTC-7, W wrote:
> On Tuesday, July 27, 2021 at 2:02:23 PM UTC-4, Mike Collins wrote:
> > https://www.space.com/universe-three-dimensional-donut?utm_source=Selligent&utm_medium=email&utm_campaign=20210721_SDC_Newsletter_Adhoc&utm_content=20210721_SDC_Newsletter_Adhoc+&utm_term=3175915&m_i=he35HP3dN9r%2BbbLWDvlRILuFPVGk5Pk5wtOvd_k0TBg7ne5MOXAFi8kMZY%2BgF9ohf4vOMa7%2BjoiP9nVYcCrmUSkcLVLf75Bthv&lrh=035e553a0a93d2128307d9417c97e4cc12a02e3fc84d6a4a40a08a0d089a7741&M_BT=5043708734676
> >
> >
> No, it's a coffee mug.

Can't be coffee mug?
Universe have no handles!

On Thursday, July 29, 2021 at 3:05:27 PM UTC-4, StarDust wrote:
> On Thursday, July 29, 2021 at 8:37:03 AM UTC-7, W wrote:
> > On Tuesday, July 27, 2021 at 2:02:23 PM UTC-4, Mike Collins wrote:
> > > https://www.space.com/universe-three-dimensional-donut?utm_source=Selligent&utm_medium=email&utm_campaign=20210721_SDC_Newsletter_Adhoc&utm_content=20210721_SDC_Newsletter_Adhoc+&utm_term=3175915&m_i=he35HP3dN9r%2BbbLWDvlRILuFPVGk5Pk5wtOvd_k0TBg7ne5MOXAFi8kMZY%2BgF9ohf4vOMa7%2BjoiP9nVYcCrmUSkcLVLf75Bthv&lrh=035e553a0a93d2128307d9417c97e4cc12a02e3fc84d6a4a40a08a0d089a7741&M_BT=5043708734676
> > >
> > >
> > No, it's a coffee mug.
> Can't be coffee mug?
> Universe have no handles!

Doughnuts and coffee mugs have the same topology.

On Thursday, July 29, 2021 at 1:17:02 PM UTC-7, W wrote:
> On Thursday, July 29, 2021 at 3:05:27 PM UTC-4, StarDust wrote:
> > On Thursday, July 29, 2021 at 8:37:03 AM UTC-7, W wrote:
> > > On Tuesday, July 27, 2021 at 2:02:23 PM UTC-4, Mike Collins wrote:
> > > > https://www.space.com/universe-three-dimensional-donut?utm_source=Selligent&utm_medium=email&utm_campaign=20210721_SDC_Newsletter_Adhoc&utm_content=20210721_SDC_Newsletter_Adhoc+&utm_term=3175915&m_i=he35HP3dN9r%2BbbLWDvlRILuFPVGk5Pk5wtOvd_k0TBg7ne5MOXAFi8kMZY%2BgF9ohf4vOMa7%2BjoiP9nVYcCrmUSkcLVLf75Bthv&lrh=035e553a0a93d2128307d9417c97e4cc12a02e3fc84d6a4a40a08a0d089a7741&M_BT=5043708734676
> > > >
> > > >
> > > No, it's a coffee mug.
> > Can't be coffee mug?
> > Universe have no handles!
> Doughnuts and coffee mugs have the same topology.

Doughnuts have no handles!
You lost!
🙄

On Thursday, July 29, 2021 at 6:38:55 PM UTC-4, StarDust wrote:
> On Thursday, July 29, 2021 at 1:17:02 PM UTC-7, W wrote:
> > On Thursday, July 29, 2021 at 3:05:27 PM UTC-4, StarDust wrote:
> > > On Thursday, July 29, 2021 at 8:37:03 AM UTC-7, W wrote:
> > > > On Tuesday, July 27, 2021 at 2:02:23 PM UTC-4, Mike Collins wrote:
> > > > > https://www.space.com/universe-three-dimensional-donut?utm_source=Selligent&utm_medium=email&utm_campaign=20210721_SDC_Newsletter_Adhoc&utm_content=20210721_SDC_Newsletter_Adhoc+&utm_term=3175915&m_i=he35HP3dN9r%2BbbLWDvlRILuFPVGk5Pk5wtOvd_k0TBg7ne5MOXAFi8kMZY%2BgF9ohf4vOMa7%2BjoiP9nVYcCrmUSkcLVLf75Bthv&lrh=035e553a0a93d2128307d9417c97e4cc12a02e3fc84d6a4a40a08a0d089a7741&M_BT=5043708734676
> > > > >
> > > > >
> > > > No, it's a coffee mug.
> > > Can't be coffee mug?
> > > Universe have no handles!
> > Doughnuts and coffee mugs have the same topology.
> Doughnuts have no handles!
> You lost!
> 🙄

Who said doughnuts have handles?

Doughnuts and coffee mugs have the same topology.

I win. You lose.

On Thursday, July 29, 2021 at 3:38:55 PM UTC-7, StarDust wrote:
> On Thursday, July 29, 2021 at 1:17:02 PM UTC-7, W wrote:
> > Doughnuts and coffee mugs have the same topology.
> Doughnuts have no handles!
> You lost!
> 🙄

https://phys.org/news/2016-10-coffee-donut-topology.html

Even a blind chicken can sometimes find the corn...

On Tuesday, 27 July 2021 at 14:02:23 UTC-4, Mike Collins wrote:
> https://www.space.com/universe-three-dimensional-donut?utm_source=Selligent&utm_medium=email&utm_campaign=20210721_SDC_Newsletter_Adhoc&utm_content=20210721_SDC_Newsletter_Adhoc+&utm_term=3175915&m_i=he35HP3dN9r%2BbbLWDvlRILuFPVGk5Pk5wtOvd_k0TBg7ne5MOXAFi8kMZY%2BgF9ohf4vOMa7%2BjoiP9nVYcCrmUSkcLVLf75Bthv&lrh=035e553a0a93d2128307d9417c97e4cc12a02e3fc84d6a4a40a08a0d089a7741&M_BT=5043708734676

Might as well be infinite anyway:

"We live in an expanding universe, and at large scales the universe is expanding at a rate that is faster than the speed of light, so you could never catch up and complete the loop."

I prefer pretzels-

https://upload.wikimedia.org/wikipedia/commons/e/e9/Kepler_Mars_retrograde.jpg

This is for astronomers rather than the theoretical riff-raff as it amounts to the motion of the Earth and Mars together using Mars and the fixed stellar background as a gauge-

"Copernicus, by attributing a single annual motion to the earth, entirely rids the planets of these extremely intricate coils,leading the individual planets into their respective orbits,quite bare and very nearly circular. In the period of time shown in the diagram, Mars traverses one and the same orbit as many times as the 'garlands' you see looped towards the centre, with one extra, making nine times, while at the same time the Earth repeats its circle sixteen times " Kepler Astronomia Nova 1609

Rather than throw good information after bad, the mistake of theorists since Newton is to imagine Kepler's pretzel is geocentric and that by plonking the Sun into the centre that direct/retrograde motions disappear hence the idiosyncratic statement of Sir Isaac and his absolute/relative space and motion-

"For to the earth planetary motions appear sometimes direct, sometimes stationary, nay, and sometimes retrograde. But from the Sun they are always seen direct,..." Newton

A lot of fun in this thread, but also a learning experience that our solar system surroundings are where real geometry is found.

On Thursday, July 29, 2021 at 9:37:03 AM UTC-6, W wrote:

> No, it's a coffee mug.

As we all know, from the famous advertisement for Mathematics,
the first volume of the LIFE science library, a doughnut is
topologically equivalent to a coffee mug!

John Savard

On Thursday, July 29, 2021 at 4:38:55 PM UTC-6, StarDust wrote:
> On Thursday, July 29, 2021 at 1:17:02 PM UTC-7, W wrote:

> > Doughnuts and coffee mugs have the same topology.

> Doughnuts have no handles!

It is precisely the handle on a coffee mug that causes it to
have the same topology as a doughnut.

A doughnut has a hole in the middle.

A coffee mug has one hole too, the place where you
put your finger when holding the handle. The dent where
you put the coffee doesn't count for anything in
topology.

The topological class of an object is the most basic
aspect of its shape; how it is connected together.
All other aspects of shape are irrelevant.

John Savard

On Friday, July 30, 2021 at 5:03:11 AM UTC-4, Quadibloc wrote:
> On Thursday, July 29, 2021 at 9:37:03 AM UTC-6, W wrote:
>
> > No, it's a coffee mug.
> As we all know, from the famous advertisement for Mathematics,
> the first volume of the LIFE science library, a doughnut is
> topologically equivalent to a coffee mug!

One morning, long ago, I looked at my coffee and doughnut and imagined that a deep dent in the rim of the doughnut would turn it into something vaguely resembling a cup with a handle. I had not heard of "topology" at the time, nor had I seen that advertisement.

On Tuesday, 27 July 2021 at 14:02:23 UTC-4, Mike Collins wrote:
> https://www.space.com/universe-three-dimensional-donut?utm_source=Selligent&utm_medium=email&utm_campaign=20210721_SDC_Newsletter_Adhoc&utm_content=20210721_SDC_Newsletter_Adhoc+&utm_term=3175915&m_i=he35HP3dN9r%2BbbLWDvlRILuFPVGk5Pk5wtOvd_k0TBg7ne5MOXAFi8kMZY%2BgF9ohf4vOMa7%2BjoiP9nVYcCrmUSkcLVLf75Bthv&lrh=035e553a0a93d2128307d9417c97e4cc12a02e3fc84d6a4a40a08a0d089a7741&M_BT=5043708734676

I like the part about expanding faster than the speed of light. Not only does it preclude seeing or reach the end of it, but it makes it much easier to avoid having to fully-explain it.

Kim Jong un health latest news!!!!!!!!!

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