Zogg From Betelgeuse Explains Why the Universe Has No Edge
http://www.universetoday.com/103790/zogg-from-betelgeuse-explains-why-the-universe-has-no-edge/

Trying to explain the topology of the Universe is really complicated… for humans. But it clearly comes naturally to Zogg the Alien from Betelgeuse. In this 10-minute video, the plucky alien vividly describes how we could have a Universe which is flat and finite, but doesn’t have an edge. How we could travel in one direction and return to our starting point, never bumping into the outside of the Universe.

What is the Universe expanding into? Nothing, it’s just expanding.

Read more: http://www.universetoday.com/103790/zogg-from-betelgeuse-explains-why-the-universe-has-no-edge/#ixzz2aYI1b300

CrazyNeutrino said:

In this 10-minute video, the plucky alien vividly describes how we could have a Universe which is flat and finite, but doesn’t have an edge. How we could travel in one direction and return to our starting point, never bumping into the outside of the Universe.

What is the Universe expanding into? Nothing, it’s just expanding.

But does he/she/it explain why we couldn’t be in a flat finite Universe that does have an edge?

The Rev Dodgson said:

CrazyNeutrino said:

In this 10-minute video, the plucky alien vividly describes how we could have a Universe which is flat and finite, but doesn’t have an edge. How we could travel in one direction and return to our starting point, never bumping into the outside of the Universe.

What is the Universe expanding into? Nothing, it’s just expanding.

But does he/she/it explain why we couldn’t be in a flat finite Universe that does have an edge?

have you watched the video?

>But does he/she/it explain why we couldn’t be in a flat finite Universe that does have an edge?

No. But there are further episodes in which it might be mentioned.

As I’ve said before, I’d assume that in models that have edges to our observable universe, whatever is on the other side of the edges would still be counted as part of the universe.

CrazyNeutrino said:

The Rev Dodgson said:

CrazyNeutrino said:

In this 10-minute video, the plucky alien vividly describes how we could have a Universe which is flat and finite, but doesn’t have an edge. How we could travel in one direction and return to our starting point, never bumping into the outside of the Universe.

What is the Universe expanding into? Nothing, it’s just expanding.

But does he/she/it explain why we couldn’t be in a flat finite Universe that does have an edge?

have you watched the video?

I have now, and it seems the answer is no, which is a shame.

Bubblecar said:

>But does he/she/it explain why we couldn’t be in a flat finite Universe that does have an edge?

No. But there are further episodes in which it might be mentioned.

As I’ve said before, I’d assume that in models that have edges to our observable universe, whatever is on the other side of the edges would still be counted as part of the universe.

Why would you assume that?

What if there isn’t anything on the other side?

If you) make that assumption, why do you not make the same assumption about a finite universe without edges?

(by the way, we aren’t talking “observable” universe here, which does have an edge)

>What if there isn’t anything on the other side?

By defining the universe itself by reference to geometric edges, you could also be said to be defining a geometric space with that shape of “hole” in it. But I suspect the more serious problem would be coming up with some physical means of providing a flat, finite universe with edges. What could these edges be, physically speaking?

Bubblecar said:

>What if there isn’t anything on the other side?

By defining the universe itself by reference to geometric edges, you could also be said to be defining a geometric space with that shape of “hole” in it. But I suspect the more serious problem would be coming up with some physical means of providing a flat, finite universe with edges. What could these edges be, physically speaking?

They could be where space stops.

I must say, it seems a little strange to me that people are apparently quite happy with portals in flat space, but not with space having a boundary.

>They could be where space stops.

Yes but why should it? You need some kind of physical reason.

I think the “portals” idea is a way of presenting higher dimensional topology as experienced by lower dimensional beings.

Bubblecar said:

>They could be where space stops.

Yes but why should it? You need some kind of physical reason.

There could be any number of reasons. Just because we don’t know doesn’t mean it doesn’t happen.

Bubblecar said:

I think the “portals” idea is a way of presenting higher dimensional topology as experienced by lower dimensional beings.

Then why describe it as flat?

The Rev Dodgson said:

Bubblecar said:

>They could be where space stops.

Yes but why should it? You need some kind of physical reason.

There could be any number of reasons. Just because we don’t know doesn’t mean it doesn’t happen.

Bubblecar said:

I think the “portals” idea is a way of presenting higher dimensional topology as experienced by lower dimensional beings.

Then why describe it as flat?

Stepping in a slide zone.. Moody Blues..

>There could be any number of reasons. Just because we don’t know doesn’t mean it doesn’t happen.

Hmm, sounds like an orphan geometry without a cosmology to account for it.

>Then why describe it as flat?

Flatness refers to the universe on the largest scale, and can be described in any number of dimensions.

This 2-part series of SciAm articles helps explain what’s meant by “flat”:

http://blogs.scientificamerican.com/degrees-of-freedom/2011/07/25/what-do-you-mean-the-universe-is-flat-part-i/

I haven’t seen the video yet but does Zogg explain when he came from?

If you have ever tried to photograph one of these beings, which normally believe they are safer on your finger or the lens barrel than looking down it.. then you’d realise that there is no flat side of the universe.

Warnings please roughbarked, for the arachnophobes.

Bubblecar said:

Warnings please roughbarked, for the arachnophobes.

Sorry DA and Alex.. is it?

Bubblecar said:

>There could be any number of reasons. Just because we don’t know doesn’t mean it doesn’t happen.

Hmm, sounds like an orphan geometry without a cosmology to account for it.

Can you try some different words. At the moment I have no idea what you mean.

The Rev Dodgson said:

Bubblecar said:

>There could be any number of reasons. Just because we don’t know doesn’t mean it doesn’t happen.

Hmm, sounds like an orphan geometry without a cosmology to account for it.

Can you try some different words. At the moment I have no idea what you mean.

♫Lost In A Lost World | The Moody Blues | Seventh Sojourn♪♩

What I mean is that without more physical detail, it may be impossible to actually evaluate whether or not your proposal is possible.

Bubblecar said:

What I mean is that without more physical detail, it may be impossible to actually evaluate whether or not your proposal is possible.

But that applies to many hypotheses. Why dismiss this particular hypothesis, whilst accepting other equally untestable hypotheses as being possible?

If you are just looking for some more specific hypotheses, two obvious possibilities are:

1) Space may become gradually more diffuse, and eventually come to a point where there is none left at all, much like a planet’s atmosphere.

2) There may be a boundary where matter and light cannot pass through, so bounce off, as illustrated in the video.

The Rev Dodgson said:

Bubblecar said:

What I mean is that without more physical detail, it may be impossible to actually evaluate whether or not your proposal is possible.

But that applies to many hypotheses. Why dismiss this particular hypothesis, whilst accepting other equally untestable hypotheses as being possible?

If you are just looking for some more specific hypotheses, two obvious possibilities are:

1) Space may become gradually more diffuse, and eventually come to a point where there is none left at all, much like a planet’s atmosphere.

2) There may be a boundary where matter and light cannot pass through, so bounce off, as illustrated in the video.

I think 2 may be a little unfashionable in the sense that it’s very ‘box like’ and implies an ‘outside’

diddly-squat said:

The Rev Dodgson said:

Bubblecar said:

What I mean is that without more physical detail, it may be impossible to actually evaluate whether or not your proposal is possible.

But that applies to many hypotheses. Why dismiss this particular hypothesis, whilst accepting other equally untestable hypotheses as being possible?

If you are just looking for some more specific hypotheses, two obvious possibilities are:

1) Space may become gradually more diffuse, and eventually come to a point where there is none left at all, much like a planet’s atmosphere.

2) There may be a boundary where matter and light cannot pass through, so bounce off, as illustrated in the video.

I think 2 may be a little unfashionable in the sense that it’s very ‘box like’ and implies an ‘outside’

Both imply an “outside”, but what is wrong with that? (Other than being unfashionable)

The Rev Dodgson said:

diddly-squat said:

The Rev Dodgson said:

But that applies to many hypotheses. Why dismiss this particular hypothesis, whilst accepting other equally untestable hypotheses as being possible?

If you are just looking for some more specific hypotheses, two obvious possibilities are:

1) Space may become gradually more diffuse, and eventually come to a point where there is none left at all, much like a planet’s atmosphere.

2) There may be a boundary where matter and light cannot pass through, so bounce off, as illustrated in the video.

I think 2 may be a little unfashionable in the sense that it’s very ‘box like’ and implies an ‘outside’

Both imply an “outside”, but what is wrong with that? (Other than being unfashionable)

nothing wrong other than it raises a lot of unanswerable questions – but this is cosmology after all…

The Rev Dodgson said:

CrazyNeutrino said:

The Rev Dodgson said:

But does he/she/it explain why we couldn’t be in a flat finite Universe that does have an edge?

have you watched the video?

I have now, and it seems the answer is no, which is a shame.

yes I see what you mean now

susskind, cosmology lectures.

10 lectures and about 21 hours all up. might go into cosmology in a bit more depth. i’ve only watched the first one so far.