speed of light

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Hey there.

Does anybody know how much the speed of light is decreasing by, and at what rate? If light travels at one hundred and eighty six thousand two hundred and two miles a second now, is there any way that we can figure out what speed it was travelling at when the universe burst into being?

Entropy increases in a closed system, so light must be slowing down... what I want to know is, how do we prove it, and measure the slow down? Is it even possible?

Thank you.

Be careful, how do you know that light is slowing, the rate of time passing might be changing.

Some measurements of the decay rate of some radioisotopes have suggested that their decay rate is not constant. One explanation is that it is due to some change in the rate at which time passes.

http://www.astroengine.com/?p=1382

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Health is a state of physical, mental and social wellbeing and not merely the absence of disease or infirmity I am not a jigsaw, I am a free man !

Diagnosed under the DSM5 rules with autism spectrum disorder, under DSM4 psychologist said would have been AS (299.80) but I suspect that I am somewhere between 299.80 and 299.00 (Autism) under DSM4.

Be careful, how do you know that light is slowing, the rate of time passing might be changing.

Some measurements of the decay rate of some radioisotopes have suggested that their decay rate is not constant. One explanation is that it is due to some change in the rate at which time passes.

http://www.astroengine.com/?p=1382

_________________
Health is a state of physical, mental and social wellbeing and not merely the absence of disease or infirmity I am not a jigsaw, I am a free man !

Diagnosed under the DSM5 rules with autism spectrum disorder, under DSM4 psychologist said would have been AS (299.80) but I suspect that I am somewhere between 299.80 and 299.00 (Autism) under DSM4.

Time is a human concept. It isn't actually real. No more so than good and evil. You percieve it, certainly, but it is not real.

Time doesn't "pass". There is no forward or backwards. No variable rate of time. It simply is "now", and always has been "now", and will always be "now".

The concept humans percieve to be time, is a quantified aspect of change, relative to a percieved constant. Ie, a day is a rotaion of the Earth upon it's axis, etc. But, in the end, we will find that all such percieved "constants" are not. Nor would it matter if it was.

~NS

I do understand all that... but despite that, we do know that entropy increases, and things slowing down is a means by which, despite our limited perceptions, we can measure that decay. So, is there any way to measure the increase of entropy as it pertains to light speed, or are we doomed to fail in the attempt?

I suppose the first thing in existence was light, and as it looks like we're in a closed system, there is nothing external against which we can measure the decay of light speed and the running down of the universe. If light exploded into being at the very instant the universe came into being, then yes, Woodpecker, you're right, time would also be slowing down, so there's no way to measure it.

Grrr...

The speed of light is a constant value; it neither increases nor decreases. As a massless wavicle (both a particle and a wave, depending on how you look at it), it cannot exist at any other "speed". It can be neither accelerated nor decelerated (although the speed of light does depend on the medium through which the wavicle must propagate - the thicker the medium, the lower the speed is). As a photon loses energy, its wavelength grows longer - the energies of the Big Bang can be detected in the microwave range, at the equivalent energy of 3 degrees above absolute zero - but the velocity remains constant.

Particles with mass do decrease in velocity as their energy levels drop. In fact, massive particles can't achieve lightspeed - as the velocity increases, so does the mass, and thus further acceleration requires more energy. In order to accelerate a massive particle to lightspeed, it would have to acquire infinite mass, and thus infinite energy. (To exceed this velocity, then, would require transfinite energies - this is why you can't go faster than light in an Einsteinian plenum. Fictional FTL drives generally resort to non-Einsteinian universes, like Star Trek's subspace.)

I may be horribly mistaken, as this is an interest I simply do not have the required intellect, but I thought Einstein's theory of relativity did not account for the expansion of the universe and scientists have calculated objects at the edge of the universe to be moving faster than the speed of light, which would give reason to believe our universe may be larger than we can ever determine, as objects may be unseen due to moving away from us faster than their light can reach us.

Thanks, ruveyn.

Two clarifications that should help:

1) The first thing in the universe was not light. Light came after photons were formed from the earlier interactions of subatomic particles. Photons formed very early, but they were not the first to form.

2) Einstein's cosmological constant (what ruveyn called his greatest blunder) has come back into vogue as a partial explanation for the observed increasing rate of expansion in the universe. But this rate, which would seem to require galaxies to be moving or have moved away from us at greater than the speed of light, is accounted for currently by the expansion of the fabric of spacetime itself, an effect that has not been explained entirely satisfactorily at present. Dark matter, dark energy, and exotic particles with names like MACHOs or WIMPs are popular explanations. Which if any will prove correct remains to be seen.

Also, the math underlying much of cosmology is a gigantic mess. Its primary redeeming feature is that it works so well in all cases that anyone has tried it in.

The speed of light does not change!! !! !

actually it does change when it passes thru optical material like water or glass ( which is why prisms and lens can bend light). But the over all speed of light in empty space does not change.

So where do you get this nonsense about light slowing down from?

Its true that mechanical objects slow due to entropy (your car running out of gas), but light is not an object. It is itself pure energy.

Indeed the creation of light is itsself part of the dispersal of energy that is entropy.
The light given off by a fire is wasted energy from the coal consumed in the firebox of a steam locomotive for example.

The speed of light does not change!! !! !

actually it does change when it passes thru optical material like water or glass ( which is why prisms and lens can bend light). But the over all speed of light in empty space does not change.

So where do you get this nonsense about light slowing down from?

Its true that mechanical objects slow due to entropy (your car running out of gas), but light is not an object. It is itself pure energy.

Indeed the creation of light is itsself part of the dispersal of energy that is entropy.
The light given off by a fire is wasted energy from the coal consumed in the firebox of a steam locomotive for example.

Questions for yall. I don't need the answers, I'd prefer you to ponder them for yourself for a while and come to whatever conclusions you come to.

What exactly is the speed of light relative to?
Is it some sort of universal constant point by which all light is relative?
Is light speed relative to the source of the light?

If a fly flies 1 mph forward on a bus traveling 50 mph, how fast is the fly traveling?
More importantly, the bus is driving on a planet spining around, how fast is the fly going now?
Oh, and the planet is orbiting a star, the star is traveling in a galaxy, and the galaxy is moving too...so, how fast is that fly going?

The point of relativity is of the utmost importance, as two photons traveling towards each other, relative to one another, are traveling twice the speed of light. But wait, that's unpossible you say?

Point I'm getting at, is, knowing what constant by which you measure the speed of light is quite important. If that constant isn't as constant as you think it is, everything based on your preconceptions will be flawed.

~NS

Thank you all very much for your input. Much to think and chew on, and I'm sure it will keep me busy.

showman, this "nonsense" about whether the speed of light changed was my wondering something, I didn't get it from anywhere, I simply wanted to understand the subject better... hence the question. From the very good feedback I've receieved, I've realised that the mistake I made was imagining light travelling through a Newtonian model, which I should have realised won't make sense outside of a terrestrial and three dimensional model. Because I've been able to think about this, I now understand instead of just "knowing" that the speed of light can't be measured, and doesn't change. Thank you guys very much for all your pointers, and other leads to follow up on. I love the fact that I can ask a question like that here, and get such well reasoned and knowledgeable answers. You guys are awesome!