Total Posts:11|Showing Posts:1-11
Jump to topic:

A Flat Universe: Is Lawrence Krauss right?

tejretics
Posts: 6,086
Add as Friend
Challenge to a Debate
Send a Message
5/16/2015 3:09:03 AM
Posted: 1 year ago
As seen in this video, physicist Lawrence Krauss says we can use general relativity to weigh all galactic clusters, dark matter and dark energy in the universe, and, with that, find the curvature of the universe. As many of you will know, there are three plausible structures for the curvature of the universe: closed, open and flat, which affects the sum of net energy and the rate of expansion. Krauss says we know that there is a 99% chance that the universe is flat, thus the sum of net energy in the universe is precisely zero [https://en.wikipedia.org...].

Is this true? Any opinions?
"Where justice is denied, where poverty is enforced, where ignorance prevails, and where any one class is made to feel that society is an organized conspiracy to oppress, rob and degrade them, neither persons nor property will be safe." - Frederick Douglass
R0b1Billion
Posts: 3,732
Add as Friend
Challenge to a Debate
Send a Message
5/16/2015 11:58:01 AM
Posted: 1 year ago
How can we weigh all the stuff in the universe if there's all that dark matter and energy throwing off our calculations?
Beliefs in a nutshell:
- The Ends never justify the Means.
- Objectivity is secondary to subjectivity.
- The War on Drugs is the worst policy in the U.S.
- Most people worship technology as a religion.
- Computers will never become sentient.
Envisage
Posts: 3,646
Add as Friend
Challenge to a Debate
Send a Message
5/16/2015 4:15:40 PM
Posted: 1 year ago
At 5/16/2015 11:58:01 AM, R0b1Billion wrote:
How can we weigh all the stuff in the universe if there's all that dark matter and energy throwing off our calculations?

If it has mass, then it has gravity. if it has gravity, then it bends light. if it bends light, then we weigh it with gravitational lensing techniques. Thus regardless of the nature of the mass, we can weigh it - thus dark matter/energy doesn't throw off anything.
Subutai
Posts: 3,189
Add as Friend
Challenge to a Debate
Send a Message
5/16/2015 9:54:17 PM
Posted: 1 year ago
To me, a flat universe just makes sense. For one thing, in a flat universe, the net energy is zero, which agrees with the laws of thermodynamics. For another, a flat universe would be infinite, and it's a bit hard to imagine a bounded universe, for what is it bounded from? Plus, a flat universe is a direct result of inflation.
I'm becoming less defined as days go by, fading away, and well you might say, I'm losing focus, kinda drifting into the abstract in terms of how I see myself.
n7
Posts: 1,360
Add as Friend
Challenge to a Debate
Send a Message
5/16/2015 9:59:54 PM
Posted: 1 year ago
According to Nasa, yes it's true within a 0.4% margin of error.

http://map.gsfc.nasa.gov...
404 coherent debate topic not found. Please restart the debate with clear resolution.


Uphold Marxist-Leninist-Maoist-Sargonist-n7ism.
tejretics
Posts: 6,086
Add as Friend
Challenge to a Debate
Send a Message
5/17/2015 12:28:24 AM
Posted: 1 year ago
At 5/16/2015 9:59:54 PM, n7 wrote:
According to Nasa, yes it's true within a 0.4% margin of error.

http://map.gsfc.nasa.gov...

Hmmm .... Krauss says it's true with a 1% margin of error, but cool.
"Where justice is denied, where poverty is enforced, where ignorance prevails, and where any one class is made to feel that society is an organized conspiracy to oppress, rob and degrade them, neither persons nor property will be safe." - Frederick Douglass
tejretics
Posts: 6,086
Add as Friend
Challenge to a Debate
Send a Message
5/17/2015 12:29:01 AM
Posted: 1 year ago
At 5/16/2015 9:54:17 PM, Subutai wrote:
To me, a flat universe just makes sense. For one thing, in a flat universe, the net energy is zero, which agrees with the laws of thermodynamics. For another, a flat universe would be infinite, and it's a bit hard to imagine a bounded universe, for what is it bounded from? Plus, a flat universe is a direct result of inflation.

The above was the first thing I thought when I saw it, because zero-energy universe = no need for God :P
"Where justice is denied, where poverty is enforced, where ignorance prevails, and where any one class is made to feel that society is an organized conspiracy to oppress, rob and degrade them, neither persons nor property will be safe." - Frederick Douglass
Sidewalker
Posts: 3,713
Add as Friend
Challenge to a Debate
Send a Message
5/17/2015 8:21:58 PM
Posted: 1 year ago
At 5/16/2015 3:09:03 AM, tejretics wrote:


As seen in this video, physicist Lawrence Krauss says we can use general relativity to weigh all galactic clusters, dark matter and dark energy in the universe, and, with that, find the curvature of the universe. As many of you will know, there are three plausible structures for the curvature of the universe: closed, open and flat, which affects the sum of net energy and the rate of expansion. Krauss says we know that there is a 99% chance that the universe is flat, thus the sum of net energy in the universe is precisely zero [https://en.wikipedia.org...].

Is this true? Any opinions?

In my opinion, Krauss is just conjuring with numbers, he making assumptions with a targeted symmetry that just isn't warranted, it might suit our sense of symmetry to work out the numbers in that way, but it' isn't based on any evidence.

All we have to work with is the "observable" universe, and there is no way to know how much Universe lays beyond what we can observe. All we can observe is what was 13.8 billion years out when the light was emitted, it's co-moving which is to say that presumably it's source has continuously been moving out in the 13.8 billion years since , so at best what we are talking about is an observable universe that is roughly 90 to 95 billion light years across. There is certainly no reason to assume the visible boundary is the edge, and there is no possible way to know what lays beyond that, there could be another two or three hundred billion light years of universe out there, it could be infinite, and there is just no way whatsoever to know.
"It is one of the commonest of mistakes to consider that the limit of our power of perception is also the limit of all there is to perceive." " C. W. Leadbeater
Envisage
Posts: 3,646
Add as Friend
Challenge to a Debate
Send a Message
5/17/2015 8:29:06 PM
Posted: 1 year ago
At 5/17/2015 8:21:58 PM, Sidewalker wrote:
At 5/16/2015 3:09:03 AM, tejretics wrote:


As seen in this video, physicist Lawrence Krauss says we can use general relativity to weigh all galactic clusters, dark matter and dark energy in the universe, and, with that, find the curvature of the universe. As many of you will know, there are three plausible structures for the curvature of the universe: closed, open and flat, which affects the sum of net energy and the rate of expansion. Krauss says we know that there is a 99% chance that the universe is flat, thus the sum of net energy in the universe is precisely zero [https://en.wikipedia.org...].

Is this true? Any opinions?

In my opinion, Krauss is just conjuring with numbers, he making assumptions with a targeted symmetry that just isn't warranted, it might suit our sense of symmetry to work out the numbers in that way, but it' isn't based on any evidence.

All we have to work with is the "observable" universe, and there is no way to know how much Universe lays beyond what we can observe. All we can observe is what was 13.8 billion years out when the light was emitted, it's co-moving which is to say that presumably it's source has continuously been moving out in the 13.8 billion years since , so at best what we are talking about is an observable universe that is roughly 90 to 95 billion light years across. There is certainly no reason to assume the visible boundary is the edge, and there is no possible way to know what lays beyond that, there could be another two or three hundred billion light years of universe out there, it could be infinite, and there is just no way whatsoever to know.

How large the actual univers is irrelevant to the question of whether or not the universe is geometrically flat. The techniques used to measure this work either way. It's a well known fact that the universe is much larger than the observable universe, anyway, but that doesn't change the fact that we know that ~14 billion years ago everything was together in a very small, dense, point. Thus, the physics works out regardless of how much the universe has expanded since.
Sidewalker
Posts: 3,713
Add as Friend
Challenge to a Debate
Send a Message
5/18/2015 10:46:50 AM
Posted: 1 year ago
At 5/17/2015 8:29:06 PM, Envisage wrote:
At 5/17/2015 8:21:58 PM, Sidewalker wrote:
At 5/16/2015 3:09:03 AM, tejretics wrote:


As seen in this video, physicist Lawrence Krauss says we can use general relativity to weigh all galactic clusters, dark matter and dark energy in the universe, and, with that, find the curvature of the universe. As many of you will know, there are three plausible structures for the curvature of the universe: closed, open and flat, which affects the sum of net energy and the rate of expansion. Krauss says we know that there is a 99% chance that the universe is flat, thus the sum of net energy in the universe is precisely zero [https://en.wikipedia.org...].

Is this true? Any opinions?

In my opinion, Krauss is just conjuring with numbers, he making assumptions with a targeted symmetry that just isn't warranted, it might suit our sense of symmetry to work out the numbers in that way, but it' isn't based on any evidence.

All we have to work with is the "observable" universe, and there is no way to know how much Universe lays beyond what we can observe. All we can observe is what was 13.8 billion years out when the light was emitted, it's co-moving which is to say that presumably it's source has continuously been moving out in the 13.8 billion years since , so at best what we are talking about is an observable universe that is roughly 90 to 95 billion light years across. There is certainly no reason to assume the visible boundary is the edge, and there is no possible way to know what lays beyond that, there could be another two or three hundred billion light years of universe out there, it could be infinite, and there is just no way whatsoever to know.

How large the actual univers is irrelevant to the question of whether or not the universe is geometrically flat.

Nonsense, you don't understand the physics or the mathematics being used, and it just doesn't matter what your girlfriend tries to tell you, size matters!

The techniques used to measure this work either way.

The "techniques" are mathematical rather than observational, and the mathematics of these particular "techniques" only apply when certain self-fulfilling assumptions are made. There is no evidence whatsoever that the global universe is a differentiable manifold, but the calculus only works if it is, so we make that assumption, then we apply the mathematics, and guess what, that "technique" tells us, it ells us it"s a differentiable manifold, go figure. There is also no way to know whether the universe is finite or infinite, and if it's finite, we can't know if it"s bounded or not, but the math being used doesn't apply to an infinite universe or to a finite universe with boundaries, so both possible conditions are inherently excluded by the process used to make the determination.

It's a well known fact that the universe is much larger than the observable universe, anyway, but that doesn't change the fact that we know that ~14 billion years ago everything was together in a very small, dense, point.

Yeah, I know, and the universe was in that initial state before inflation occurred, so that has nothing whatsoever to do with its current geometry or its topology. It's also a well-known fact that the only evidence we have to work with is the "observable" universe, and so the calculations and the "measurements" can only be made and applied locally, which is to say they are meaningless in terms of whether the global universe is flat or not.

Thus, the physics works out regardless of how much the universe has expanded since.

Nope, the physics does not "work out" regardless, explicit assumptions are necessary in order to make the physics "work out", but those assumptions are not conclusions of the physics that determine the fact, they are assumptions made before the fact. The very concept that "everything was together in a very small, dense, point" is an initial condition that would be finite and bounded, so it is explicitly excluded from consideration in the "technique" being applied, your so called technique considers the initial pre-inflation condition to be an impossible state.
"It is one of the commonest of mistakes to consider that the limit of our power of perception is also the limit of all there is to perceive." " C. W. Leadbeater
Yassine
Posts: 2,617
Add as Friend
Challenge to a Debate
Send a Message
5/26/2015 9:46:42 PM
Posted: 1 year ago
At 5/16/2015 4:15:40 PM, Envisage wrote:
At 5/16/2015 11:58:01 AM, R0b1Billion wrote:
How can we weigh all the stuff in the universe if there's all that dark matter and energy throwing off our calculations?

If it has mass, then it has gravity. if it has gravity, then it bends light. if it bends light, then we weigh it with gravitational lensing techniques. Thus regardless of the nature of the mass, we can weigh it - thus dark matter/energy doesn't throw off anything.

- I just saw this! -_-
Current Debates:

Islam is not a religion of peace vs. @ Lutonator:
* http://www.debate.org...