Author Topic: New Evidence Our Universe Might Be Both Curved and Finite  (Read 1062 times)

Offline Shiranu

New Evidence Our Universe Might Be Both Curved and Finite
« on: December 03, 2019, 01:14:49 AM »

I absolutely love this channel. So much of the things he talks about go over my head, but I can always at least keep up enough to get the main point and sometimes some of the finer details.




One really interesting thing I had never heard was that when you look at the Background Cosmic Radiation, the earliest picture of the universe we can ever have, what you are seeing in those specks are sound waves that bounced around for several hundred thousand years after the Big Bang, and as the universe cooled the sound waves essentially froze in place.

That is absolutely insane.

https://www.youtube.com/watch?v=F2s7vyKucis




Offline Baruch

Re: New Evidence Our Universe Might Be Both Curved and Finite
« Reply #1 on: December 03, 2019, 08:56:19 AM »
Dense hot balls of gas aren't silent.  If there wasn't 93 million miles of vacuum between the Earth and the Sun, we would be deafened by the continuous thermonuclear roar (which appears responsible for the over-heating of the corona).
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Re: New Evidence Our Universe Might Be Both Curved and Finite
« Reply #2 on: December 03, 2019, 01:33:38 PM »
I saw that yesterday. I'll let the experts fight it out, and then let me know what they decide. But if the universe isn't spatially infinite, does that mean there is a "outside" of it? I've heard that there's a hell of a universe next door, but you know how neighbors can be...
God Not Found
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Offline Baruch

Re: New Evidence Our Universe Might Be Both Curved and Finite
« Reply #3 on: December 03, 2019, 06:13:20 PM »
I saw that yesterday. I'll let the experts fight it out, and then let me know what they decide. But if the universe isn't spatially infinite, does that mean there is a "outside" of it? I've heard that there's a hell of a universe next door, but you know how neighbors can be...

One old idea, is that if you look far enough, it loops.  You see the back of your head (with fun house gravitational distortion).
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Re: New Evidence Our Universe Might Be Both Curved and Finite
« Reply #4 on: December 04, 2019, 10:58:06 AM »
Sometimes I get the feeling that there might be a bigger as yet inarticulate problem in cosmology.

In order to make the observations fit to the broad theories of the early 20th century (big bang, inflation, all that) it seems as various 'black boxes' keep getting added to the theory to account for incongruities. Dark mater, dark energy, curvature, and so on. It reminds me a little too vividly of the pre Copernican days of astronomy when the geocentric model of the Universe was trying to explain the ever more through and precise observations of the movements of the planets. Starting with the assumption of the Earth being at the center and the planets (in the parlance of the time that includes the Moon and Sun) moving in circles around the Earth, they had to add epicycles, cycles with in cycles, to account for planets moving in retrograde. They had a flawed theory and kept adding fudge factors to keep the theory fitted to observations. One of the problems that early proponents of a Heliocentric model of the faced was that their theories could not fit to the observations as well as the Geocentric epicycles, at least until Newtonian Mechanics could churn out more precise predictions.

I sure don't know what's going on in the greater cosmos, but seeing the subtle fiddling to keep out theories in line with the observations makes me suspect that there is something deeper in current cosmological theories that is at least a little out of skew.

Having gone through some commentaries on the new research I notice that one of the goals was to address an incongruity between MBR based estimates for the age of the Universe and Standard Candle based observations, and yet the new more curved model spits out an estimated age of the Universe even further from the Standard Candle based estimates. Also, some have suggested that the amount of heavy elements in the Universe is higher than can be easily accounted for in the current estimated age of the Universe.

I don't know what's up, one thing I am curious about in the new research is how much curvature they figure their is, and from that a supposition of how big the Universe is if it in fact is finite.

Offline Baruch

Re: New Evidence Our Universe Might Be Both Curved and Finite
« Reply #5 on: December 04, 2019, 12:55:20 PM »
Cosmological size is a paradox.  Much cosmology claims that the universe is bigger than the 3.5K horizon shows (if you could take a POV outside our location).  Which is to say, if you took a move 10 billion light years in any direction, you would essentially see a similar 3.5 K horizon at the same distance (like a ship on the round Earth).  So size and visibility aren't the same thing.  If that is so (and how can we test?), then we can only see the 3.5K visible horizon distance (equal in all directions) we can't actually measure true size, in that the true size could be anything equal to or larger than the visible horizon distance allows.

And then there is the claim of a multiverse ... how do you size things when there is more than one, maybe an infinite number of .. universes?  Presumably what we learn in the LHC, is mostly about the first few instants of the Big Bang, not about how things are 13 billion years later (quark/gluon/electron plasma).

We simply can't do controlled experiments on a larger than solar system scale, and only over a very short time scale relative to cosmological time.  We can do controlled observations, but our location/time limits us.

The question of net curature of the universe (cosmological constant not zero) ties into dark energy in particular, and nobody has any theory about that, classical or quantum.  Quantum cosmology isn't even self consistent (hence search for unified theory of gravitation and QM).
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Re: New Evidence Our Universe Might Be Both Curved and Finite
« Reply #6 on: December 04, 2019, 01:28:55 PM »
Sometimes I get the feeling that there might be a bigger as yet inarticulate problem in cosmology.

In order to make the observations fit to the broad theories of the early 20th century (big bang, inflation, all that) it seems as various 'black boxes' keep getting added to the theory to account for incongruities. Dark mater, dark energy, curvature, and so on. It reminds me a little too vividly of the pre Copernican days of astronomy when the geocentric model of the Universe was trying to explain the ever more through and precise observations of the movements of the planets. Starting with the assumption of the Earth being at the center and the planets (in the parlance of the time that includes the Moon and Sun) moving in circles around the Earth, they had to add epicycles, cycles with in cycles, to account for planets moving in retrograde. They had a flawed theory and kept adding fudge factors to keep the theory fitted to observations. One of the problems that early proponents of a Heliocentric model of the faced was that their theories could not fit to the observations as well as the Geocentric epicycles, at least until Newtonian Mechanics could churn out more precise predictions.

I sure don't know what's going on in the greater cosmos, but seeing the subtle fiddling to keep out theories in line with the observations makes me suspect that there is something deeper in current cosmological theories that is at least a little out of skew.

Having gone through some commentaries on the new research I notice that one of the goals was to address an incongruity between MBR based estimates for the age of the Universe and Standard Candle based observations, and yet the new more curved model spits out an estimated age of the Universe even further from the Standard Candle based estimates. Also, some have suggested that the amount of heavy elements in the Universe is higher than can be easily accounted for in the current estimated age of the Universe.

I don't know what's up, one thing I am curious about in the new research is how much curvature they figure their is, and from that a supposition of how big the Universe is if it in fact is finite.

Steinhardt and Turok talked about the ad hoc nature of the inflationary model in their book Endless Universe:Beyond the Big Bang.





http://www.physics.princeton.edu/~steinh/endlessuniverse/index2.html

Quote
The Big Bang theory is widely regarded as the leading explanation for the origin of the universe. Yet, over the last three decades, the theory has been revised repeatedly to address such issues as how galaxies and stars first formed and why the expansion of the universe is speeding up today. Furthermore, no explanation has been found for what caused the Big Bang in the first place.

In Endless Universe, Paul J. Steinhardt and Neil Turok, both distinguished theoretical physicists, critique the Big Bang theory and recount the remarkable developments in astronomy, particle physics, and superstring theory that form the basis for a groundbreaking alternative, the “Cyclic Universe” theory. According to this theory, the Big Bang was not the beginning of time but the bridge to a past filled with endlessly repeating cycles of evolution, each accompanied by the creation of new matter and the formation of new galaxies, stars, and planets. The authors explain why the ensuing debate between these two, radically different theories will profoundly affect the future of cosmology and perhaps science, in general.


It's an excellent book that's easy to read and very informative. Here's a PDF, if you'd care to have a look:

http://www.physics.princeton.edu/~steinh/ph115/EndlessExcerpt.pdf
God Not Found
"There is a sucker born-again every minute." - C. Spellman

Re: New Evidence Our Universe Might Be Both Curved and Finite
« Reply #7 on: December 04, 2019, 02:10:46 PM »
[member=27999]Baruch[/member] In principle if we could measure the curvature of a closed universe we could figure the size of the closed space, like how one could in principle figure the curvature of the Earth by measuring the curvature of the surface with in the horizon. If we accept the most recent findings at face value, and estimate the curvature with in the observable horizon, in principle we could figure the scale of the closed system beyond the horizon. I think with expansion and relativity the size of such a universe would be relative to an assumed frame of reference.

Offline Baruch

Re: New Evidence Our Universe Might Be Both Curved and Finite
« Reply #8 on: December 04, 2019, 06:37:13 PM »
[member=27999]Baruch[/member] In principle if we could measure the curvature of a closed universe we could figure the size of the closed space, like how one could in principle figure the curvature of the Earth by measuring the curvature of the surface with in the horizon. If we accept the most recent findings at face value, and estimate the curvature with in the observable horizon, in principle we could figure the scale of the closed system beyond the horizon. I think with expansion and relativity the size of such a universe would be relative to an assumed frame of reference.

It is relative ;-)  So the question is malformed.  That and it is the 4-volume of space-time that is relevant, not the 3-volume of space (which changes with the Lorentz transformation).  If something isn't invariant (like say the standard liter of liquid volume in classical physics) then it isn't a proper comparison (as all quantitative measurement is).  What gravity added to SR, was that even with co-moving frames, their length or duration, depends on that gravitational field.  This is clearest in a stationary gravitational field, in the vertical (to center of mass) direction.  A time standard (spectrum line) moves as you change the distance to the center of mass.

http://hyperphysics.phy-astr.gsu.edu/hbase/Solar/gravproba.html#c1

The Hyperphysics web page has the best HS physics reference out there.
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Offline SGOS

Re: New Evidence Our Universe Might Be Both Curved and Finite
« Reply #9 on: December 21, 2019, 12:37:19 PM »
I sure don't know what's going on in the greater cosmos, but seeing the subtle fiddling to keep out theories in line with the observations makes me suspect that there is something deeper in current cosmological theories that is at least a little out of skew.
The same thought has occurred to me.

Offline Baruch

Re: New Evidence Our Universe Might Be Both Curved and Finite
« Reply #10 on: December 21, 2019, 12:45:17 PM »
The same thought has occurred to me.

Get some Dark Energy or Dark Matter in a solar system or Earth experiment ... and we will have something to talk about, if we survive!



Maybe not make black holes, but what would Dark Energy or Dark Matter do?  Physicists have no idea.

Actually it is European socialism that destroys Europe.
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