Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Harri on 29/12/2015 22:58:31

Title: What happens to light as universe expansion slows down?
Post by: Harri on 29/12/2015 22:58:31
Firstly, is the speed of the expanding universe slowing down?

If the answer is yes - then does the speed of light that is expanding with the universe slow down too?
Or does light continue beyond the expanding universe?
Title: Re: What happens to light as universe expansion slows down?
Post by: Space Flow on 30/12/2015 04:38:12
The speed of Universal Expansion is not only not slowing down, it is in fact accelerating in it's expansion.
That is the reason we have a placeholder name "Dark Energy" in our modern scientific vocabulary.
We do not understand what the cause of this acceleration is but acceleration is what observational evidence seems to be showing us.
We were all expecting it to be slowing down.

In 1995,Brian Schmidt led the High-Z Supernova Search Team from Australia to measure the expected deceleration of the universe using distances to Type Ia supernovae and in 1998 in the HZT paper, the first evidence was presented that the universe's expansion rate is not decelerating; it is accelerating.

The discovery of the accelerating universe was named 'Breakthrough of the Year' by Science in 1998, and Schmidt was jointly awarded the 2011 Nobel Prize in Physics along with Reiss and Perlmutter for their groundbreaking work.

The speed of light under any circumstances whatsoever can never be seen to be anything other than the speed of light.
It is a constant.
The frequency of light is affected by a variety of things including Universal Expansion, but the Speed of light remains constant for all observers all of the time.

Hope that helps..
Title: Re: What happens to light as universe expansion slows down?
Post by: Harri on 30/12/2015 19:20:57
Yes, that does help, thank you. Very interesting.

Acceleration? Is the universe accelerating away from the point of the big bang? Are there any theories I might understand to explain this acceleration?
Title: Re: What happens to light as universe expansion slows down?
Post by: Space Flow on 30/12/2015 20:10:20
Acceleration? Is the universe accelerating away from the point of the big bang? Are there any theories I might understand to explain this acceleration?
Harri, unfortunately it classifies as one of the greatest unsolved mysteries of the Universe.
There are some hypothesis popping up, but the truth is, we don't know why or how this is happening. Hence the placeholder name "Dark Energy" for the cause of this. "Dark" because we don't have a clue and "Energy" because work appears to be done in accelerating expansion.
I think one of the current most popular hypothesis, is that somehow vacuum energy is involved. We are observing the continuous creation of more and more spacetime at a current calculated rate of 74.3 plus or minus 2.1 kms per second per megaparsec (a megaparsec is roughly 3 million light-years).
If current theories are correct and spacetime contains this vacuum energy, then the vacuum energy of the Universe is continually increasing.
I at one stage a couple of months ago, had the opportunity to ask Brian Schmidt, why this does not constitute a violation of conservation laws. The answer left me not been able to formulate any further question on the subject.
Quote
Brian Schmidt;  There are no conservation laws that apply to Spacetime. If there were such laws you would be right and the accelerated expansion would be violating them. But they do not exist.

I mean what do you say to that?
Convenient??

There is a ton of material on the subject both on uTube and elsewhere on the Net. Unfortunately at this stage it is all conjecture. There is nothing I can recommend as an avenue to real understanding.
Title: Re: What happens to light as universe expansion slows down?
Post by: Harri on 01/01/2016 19:23:56
Hi Space Flow and thanks again.

So the universe is expanding at an increasing rate. According to the law of conservation of energy this shouldn't be happening? The universe must be getting extra energy from somewhere hence Dark Energy?

To pedal a bicycle faster we have to use up more energy. The energy must be there in the first place to be used. It just means the bicycle will come to a standstill earlier than if we hadn't increased the acceleration.
Can't the universe just be utilising energy what is already there/here?
Title: Re: What happens to light as universe expansion slows down?
Post by: chris on 02/01/2016 11:14:15
Quote
So the universe is expanding at an increasing rate. According to the law of conservation of energy this shouldn't be happening? The universe must be getting extra energy from somewhere hence Dark Energy?

That's right; the observations that we have suggest that the Universe is expanding, and that the rate of expansion is
increasing although this inflation is being powered by unknown physics. This is reconciled by invoking the as yet undefined, unknown and unmeasured theoretical entity dubbed "Dark Energy" as the driving force. We know that this must exist in one form or another, but no one has yet detected it or, for that matter, knows how to go about detecting it...

Title: Re: What happens to light as universe expansion slows down?
Post by: Space Flow on 02/01/2016 11:36:59
To pedal a bicycle faster we have to use up more energy. The energy must be there in the first place to be used. It just means the bicycle will come to a standstill earlier than if we hadn't increased the acceleration.
Can't the universe just be utilising energy what is already there/here?
Harri, there is certainly nothing wrong with your logic.
apart from the fact that your logic and everyone else's at the moment does not match observations.
The main problem arrises out of the fact that the Universe is supposed to be everything that is.
Yet the part of the Universe represented by spacetime is continually getting larger at an accelerating rate.
There is no energy that we can account for anywhere inside the Universe to power this.
Yet there is no outside of the Universe. It is giving a lot of our heaviest thinkers a continuous headache.
Title: Re: What happens to light as universe expansion slows down?
Post by: Harri on 02/01/2016 22:05:27
Thanks guys, really interesting.

Is everything in the universe moving away from the big bang in relatively straight waves?

What if the universe was moving away from the big bang in ever increasing waves like an ocean swell? Wouldn't the universe accelerate as the waves got higher?
Title: Re: What happens to light as universe expansion slows down?
Post by: Space Flow on 03/01/2016 05:25:19
Is everything in the universe moving away from the big bang in relatively straight waves?
Harri I have never come across any reference to a wave nature to expansion.
In fact The universe in every direction we look on the largest scales appears totally flat. The only deviation from that flatness attributable to the vicinity of matter.
There are speculations that the expansion rate has gone through a couple of changes in 13.8 Billion years. Exponentially fast at the beginning, (Inflation)
Steady expansion for about 7 Billion years,
Accelerated expansion for the last 7 billion or so years.
I can't vouch for the accuracy of those speculations but if they are true that could be seen "maybe" as a 7 billion light year wavelength????
Maybe a bit of a stretch?
Title: Re: What happens to light as universe expansion slows down?
Post by: alysdexia on 09/01/2016 19:51:48
Snell's law and Heaviside's law override Lorentz's law which overrides Schwarzschild's law.

Celerity should be a function of curvature, which hasn't done much even at the noninertial inflections of universal expansion, whose conjugates are driven by positive and negative mass and vis creation and polarization.  For small deviations in cosmic celerity see VSL.

Learn how to spell its.