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Physics, Astronomy & Cosmology / Re: How would the universe change if the speed of light increased?

« on: 05/11/2017 06:12:02 »

And this one you need to expand on " and we would also expect that the CMB radiation would be relatively uniform in temperature. " I guess you consider it following from your first statement?

It does not follow from the first statement, it follows from that fact that the speed of light changes.

If, in the past, the speed of light were greater than it is today, then we would expect that two objects (or sections of fluid, or whatever) would be able to influence each other from farther away than is possible in a constant-c universe.  If the speed of light were great enough, then that would mean that every part of the universe was interacting with every other part of the universe almost instantaneously.  You didn't have to wait 20 minutes for infrared waves to travel 20 light-minutes, it was much quicker. 

This would mean that at that time, the temperature of the entire universe would approach equilibrium much faster in a slowing-c universe than in a constant-c universe.

This would mean that the CMB radiation would be more uniform in temperature in a slowing-c universe than it would be in a constant-c universe.

The discussion would change from "why is the CMB so uniform?", to "why is the CMB so ununiform?"

There are several difficulties with that idea Cowlinator. One main come from how a 'Big Bang' is presumed to act. A inflation without a 'center' is not something that need to relate to the geometry we define, and a 'lightspeed' would not be acting the way one might expect there. There is no problem in letting 'c' be 'c' for it to connect 'nodes'. And the 'nodes' making this universe exist is defined by 'c'. You could just as easily imagine a Big Bang to be what creates the connections allowing us a universe to define.  It's very hard discussing a 'small universe' inflating unless one step away from how a 'Big Bang' is thought to act in mainstream physics.

The statement
"The CMB radiation would be more uniform in temperature in a slowing-c universe than it would be in a constant-c universe."
is true in an universe with or without inflation, and is also true in a universe with or without a big bang. 

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Physics, Astronomy & Cosmology / Re: How would the universe change if the speed of light increased?

« on: 29/10/2017 22:04:49 »

And this one you need to expand on " and we would also expect that the CMB radiation would be relatively uniform in temperature. " I guess you consider it following from your first statement?

It does not follow from the first statement, it follows from that fact that the speed of light changes.

If, in the past, the speed of light were greater than it is today, then we would expect that two objects (or sections of fluid, or whatever) would be able to influence each other from farther away than is possible in a constant-c universe.  If the speed of light were great enough, then that would mean that every part of the universe was interacting with every other part of the universe almost instantaneously.  You didn't have to wait 20 minutes for infrared waves to travel 20 light-minutes, it was much quicker. 

This would mean that at that time, the temperature of the entire universe would approach equilibrium much faster in a slowing-c universe than in a constant-c universe.

This would mean that the CMB radiation would be more uniform in temperature in a slowing-c universe than it would be in a constant-c universe.

The discussion would change from "why is the CMB so uniform?", to "why is the CMB so ununiform?"

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Physics, Astronomy & Cosmology / Re: Is it possible to survive a false vaccuum decay?

« on: 08/10/2017 21:32:36 »

I'm not worried, I'm curious.

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Physics, Astronomy & Cosmology / Is it possible to survive a false vaccuum decay?

« on: 08/10/2017 07:25:38 »

Is it possible for humans (current or future) to survive a false vaccuum decay?

For instance, I've wondered if a false vaccuum collapses into a true vaccuum that has only a very, very minute difference in energy level, then perhaps the universe wouldn't change that much, and human life could survive.

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Physics, Astronomy & Cosmology / Re: How would the universe change if the speed of light increased?

« on: 08/10/2017 02:31:11 »

"Time, space, electricity and quantum mechanics
Our imaginary experiment shows that electrical and quantum effects are inter-related. Charge is carried by electrons and protons, which are subject to (quantum) mechanical laws. It is meaningless to talk of changes in an electromagnetic constant or a quantum mechanical one alone. Asking whether the speed of light changes over time superficially appears to be a reasonable question: it makes grammatical sense. But it doesn't make scientific sense. In science, a proposition must be, in principle, testable. (For instance, if you propose that there is an invisible gorilla in the room, and that she has no mass and no effects that can be detected, then your proposition is not a scientific one.)"

The speed of light changing over time would be completely provable/falsifiable, wouldn't it? Maybe not with our current technology, but eventually, yes. The analogy to the gorilla seems unfounded.

For instance, it the speed of light slows over time, we would expect redshifting of distant light sources, and we would also expect that the CMB radiation would be relatively uniform in temperature.

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Physics, Astronomy & Cosmology / Re: How would the universe change if the speed of light increased?

« on: 08/10/2017 02:21:56 »

Times a constant with a specific kind of units.

The most natural constant to use is 1. The material of the particle with mass is made up of the energy that it can be converted into so the amounts are equal. Any other conversion factor distorts reality, but this does give us units that are more convenient to work with for normal purposes - ordinarily our experience of energy is in tapping into "flogiston" (small differences in the bonding energy between atoms in molecules), so we heavily downplay the amount of energy that is actually stored in matter by using units more appropriate to the tiny proportion that is immediately accessible.

On another issue, suppose the speed of light has been slowing down as the universe expands. The universe could be expanding at a constant rate while appearing to speed up because the functionality of everything in the universe would be running slower and slower as the speed of light reduces, with the result that we would be measuring the expansion with slowing clocks.

The square in E=MC^2 doesn't go away just because you use 1 as 'c'.  The dimensions of c^2 are distance * distance / time * time, which is not a speed, it is a speed squared.

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Physics, Astronomy & Cosmology / Re: How would the universe change if the speed of light increased?

« on: 06/10/2017 08:27:43 »

It's a constant and it's merely acting as a conversion factor between units, but the reality behind the distorted view that these units give us is that e=m.

Times a constant

Not according to relativity.

e = m times a constant.  According to relativity.  (Note the lack of apostrophe in "times")

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Physics, Astronomy & Cosmology / Re: How would the universe change if the speed of light increased?

« on: 05/10/2017 17:45:33 »

It's a constant and it's merely acting as a conversion factor between units, but the reality behind the distorted view that these units give us is that e=m.

Times a constant with a specific kind of units.

everything else would adjust to hide the difference so you would still measure it as having the same value of c.

That would be an extraordinary coincidence, unless you're basing that on some law that I'm not aware of.

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Physics, Astronomy & Cosmology / How would the universe change if the speed of light increased?

« on: 02/10/2017 01:13:17 »

How would the universe change if the speed of light were suddenly increased, somehow, to a faster speed (for example, 1 trillion times the current speed) ?

Obviously the outer event horizon of the universe would expand and we wouldn't be able to see past events so easily, but I'm curious as to how physical laws might change.

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Physics, Astronomy & Cosmology / Re: If the Moon fragmented, could pieces hit the Earth?

« on: 02/10/2017 00:54:47 »

That was a very clear explanation.  Thank you!

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Physics, Astronomy & Cosmology / If a brown dwarf gains mass to become a small red dwarf, does the radius alter?

« on: 01/10/2017 11:21:52 »

If a large brown dwarf gains mass and becomes a small red dwarf, does the radius increase, decrease, or remain (roughly) the same?

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Physics, Astronomy & Cosmology / If the Moon fragmented, could pieces hit the Earth?

« on: 01/10/2017 10:28:46 »

If the orbit of the Moon was for some reason shrunk to the Roche limit of Earth, would the fragments of Moon created be large enough to survive Earth's atmosphere and impact the surface?

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Physics, Astronomy & Cosmology / Re: What are the implications of cosmic inflation?

« on: 05/07/2017 05:40:37 »

In an expanding universe things aren't all getting larger in proportion with the expansion. If they were we would be unable to detect it!

I wouldn't say the strength of the forces change. It is the background environment that changes.

If the strength of the forces don't change, how do we detect inflation? 
How does one measure the background environment?

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Physics, Astronomy & Cosmology / Re: Cosmic inflation: confused about implications

« on: 03/07/2017 07:47:36 »

Thanks for answering, Jeffrey.

So it sounds like elementary forces change in strength as the scale of space changes.  Does the speed of light also change as the scale of space changes?

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Physics, Astronomy & Cosmology / What are the implications of cosmic inflation?

« on: 03/07/2017 02:40:09 »

I have a few questions about inflation.

Would the speed of light actually change, and/or would it be observed to change, according to an expanding metric?

In a small universe, we would measure 2 objects to be 1 meter apart, according to our meter-stick, and that light takes a certain time to travel between them.  After the universe expands (and thus our meter-stick expands), we would observe the objects to be 1 meter apart (even though the space between them had actually increased).  But would the length of time for light to travel between the objects change?

Also, back when the universe was small, our 2 objects would feel certain gravitational and electromagnetic forces from each other, based on their distance.  After the universe expands, and our metric also expands, the objects would be observed (using our expanded meter-stick) to have the same distance and volume, even though the distance and volume had actually increased because space expanded.  However, the mass would be the same (I believe).
The formulas for calculating gravity and electric force would predict that the strength of the forces would also remain the same.  Is this true, though?  Would the objects feel the same strength of gravitational pull even though there is more space in between them?

So, here are my root questions:
-- How does the scale of space affect the observed speed of light?
-- How does the scale of space affect forces which influenced by distance?
-- If the speed of light and the forces are observed to be the same before/after expansion, how is it possible to distinguish the scale of space, since the behavior is the same in all scales of reference?

Thanks!

[MOD EDIT - TITLE RE-FORMATTED AS A QUESTION, IN LINE WITH FORUM POLICY]

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Physics, Astronomy & Cosmology / What are the main sources of electromagnetic radiation?

« on: 22/02/2017 03:34:16 »

For some reason, I can't seem to find much info about this on the internet... at least, not in the form that I'm looking for it.

So far, I've come up with 2 fundamental sources of electromagnetic radiation:

- Spontaneous emission
- Annihilation

There are also things like Thermal Radiation and Gamma Radiation, but it's unclear to me if they are distinct from the above and what the underlying mechanism for them are.
There likely are also other sources that I am missing.

After searching online, every resource that lists sources of electromagnetic radiation seems to list them at the non-fundamental/macro level, e.g. "Lightning" or "The sun"

Can someone help me out here?

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Physics, Astronomy & Cosmology / Time-dilation effect on rate of event horizon growth?

« on: 31/12/2016 03:39:44 »

We know that events near an event horizon are highly time-dilated to an outside observer. 
Is the expansion of the event horizon itself time-dilated?  (That is, if the black hole quickly gained mass, and the radius of the event horizon expanded rapidly, would an outside observer see the event horizon grow at the same rate as an observer near the horizon?)

Related question: Can the radius of the event horizon grow faster than c?

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Physics, Astronomy & Cosmology / Re: Can you "ride" a gravitational wave?

« on: 22/12/2016 01:55:08 »

But we're not talking about material objects, we're talking about a point in space.

If it helps, let's say it's about a photon instead.

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Physics, Astronomy & Cosmology / Can you "ride" a gravitational wave?

« on: 18/12/2016 23:25:34 »

Assume we defined a moving point in spacetime that "rides" a gravitational wave, at the speed of light.  This point would always be between a valley and peak of the amplitude of the wave. 

Would this point experience contracting space in front of it and expanding space behind it?

If so, wouldn't this point experience all of the same effects as a point within the bubble of an Alcubierre drive?

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Physics, Astronomy & Cosmology / Re: Does Newton's shell theorem account for tidal forces?

« on: 18/12/2016 06:34:39 »

Forgive my ignorance, but what is Newton's Shell Theorem?

A spherically symmetric body affects external objects gravitationally as though all of its mass were concentrated at a point at its centre.