Speed of light question caught on Phy.org forum:

Speed of light question?
Has the speed of light always been the same since the beginning of the universe? The reason i ask is i work with a guy who is a strict creationist and he said that despite the universe appearing to be 13 billion years old, the speed of light may of been billions of times faster just after the universe's creation 6000 years ago. I wanna be able to refute his argument that the speed has not changed but i am not sure which theory or evidence which proves that light has not changed or how they know the speed was the same around 6000 years ago.

Thanks!


So just how can you answer that question, that statement by the avowed creationist and young Earther at that. Can it be shown that the rate of time has not changed in the past 10 billion years or so?

One thing that complicates the issue is that while the speed of light has not changed, space has been expanding. This creates an effect that makes it seem like the speed of light is decreasing over time.

When you refer to the rate of time - the rate with respect to what?

What difference in speed of light is neccessary to change the age of universe from (the true value of around) 13.7 billion of years to the more modest age of 6000 years? The speed of light would be at a snail's pace from the first second of the Universe. Adam and Eve couldn't even see eachother in the beginning. (And that's why the wasn't shy to eachother in their nudidity!" )

Originally posted by sonhouse
Speed of light question?
Has the speed of light always been the same since the beginning of the universe? The reason i ask is i work with a guy who is a strict creationist and he said that despite the universe appearing to be 13 billion years old, the speed of light may of been billions of times faster just after the universe's creation 6000 years ago. I w ...[text shortened]... that. Can it be shown that the rate of time has not changed in the past 10 billion years or so?

http://en.wikipedia.org/wiki/Variable_speed_of_light

I don't see how this helps creationists, though.

Originally posted by sonhouse
Speed of light question?
Has the speed of light always been the same since the beginning of the universe? The reason i ask is i work with a guy who is a strict creationist and he said that despite the universe appearing to be 13 billion years old, the speed of light may of been billions of times faster just after the universe's creation 6000 years ago. I w ...[text shortened]... that. Can it be shown that the rate of time has not changed in the past 10 billion years or so?

Why would he think the speed has changed, has there ever been any
change in the speed as long as we have been looking at it? I have
less issue with that as much as I do we don't simply know the starting
point, we know where we are now and what we think that means if we
project time backwards on where everything was. That simply shows us
where we think everything was, not that it actually was there only where
we think it was. If you don't know for sure how it started any theory,
guess, or hypothesis is just something that could have occurred not
a real clear picture of reality.
Kelly

Originally posted by sonhouse
Has the speed of light always been the same since the beginning of the universe?

If the speed of light were significantly different, then the rules of physics would be different too. If this were the case, then distant stars and galaxies would work according to different rules of physics from those near by.

Originally posted by KellyJay
Why would he think the speed has changed, has there ever been any
change in the speed as long as we have been looking at it? I have
less issue with that as much as I do we don't simply know the starting
point, we know where we are now and what we think that means if we
project time backwards on where everything was. That simply shows us
where we think ...[text shortened]... thesis is just something that could have occurred not
a real clear picture of reality.
Kelly

So are you not sure whether stars actually exist? After all, the light travelling from most of them is anywhere from thousands to billions of years old. I think the young earther in question realizes that the implication is either the universe is billions of years old, or those stars don't exist.
You say it is not a real clear picture of reality? Have you seen any Hubble photos? I think they are very clear.
Now it is possible that God put all the light into space and lined it up in a special way so as to fool us that other galaxies exist, but when he so clearly wants you to see galaxies, who are you to say they don't exist?

Originally posted by twhitehead
So are you not sure whether stars actually exist? After all, the light travelling from most of them is anywhere from thousands to billions of years old. I think the young earther in question realizes that the implication is either the universe is billions of years old, or those stars don't exist.
You say it is not a real clear picture of reality? Have yo ...[text shortened]... exist, but when he so clearly wants you to see galaxies, who are you to say they don't exist?

Or when they were created the light stream that would have taken billions of
years was made at the same time, causing them to be
"...signs, and for seasons, and for days, and years..." difficult to be a sign
for a season if it was going to take billions of years before their lights ever
hit the earth.
Kelly

Originally posted by KellyJay
Or when they were created the light stream that would have taken billions of
years was made at the same time, causing them to be
"...signs, and for seasons, and for days, and years..." difficult to be a sign
for a season if it was going to take billions of years before their lights ever
hit the earth.
Kelly

So you are speculating that God invented a whole history of the universe that never happened, and planted the evidence (light), but you won't believe it because he said something else in the Bible?
If you are comfortable with God deliberately planting false evidence, why do you not use the same argument when it comes to evolution? Why don't you simply say that God planted all those fossils as signs of some sort?

Originally posted by twhitehead
So you are speculating that God invented a whole history of the universe that never happened, and planted the evidence (light), but you won't believe it because he said something else in the Bible?
If you are comfortable with God deliberately planting false evidence, why do you not use the same argument when it comes to evolution? Why don't you simply say that God planted all those fossils as signs of some sort?

No, I'm speculating God created the universe, and you are writing the
history of all things according to what you think everything means around
you now, that is according to all you see in the here and now. Scripturally
speaking, God created everything in six days that can be taken or rejected
out of hand for whatever reason you'd like, or no reason at all just because
you want to.
Kelly

Originally posted by KellyJay
No, I'm speculating God created the universe, and you are writing the
history of all things according to what you think everything means around
you now, that is according to all you see in the here and now. Scripturally
speaking, God created everything in six days that can be taken or rejected
out of hand for whatever reason you'd like, or no reason at all just because
you want to.
Kelly

You are avoiding your previous statement. I am specifically referring to your suggestion that the stars we see never actually existed, and that the light was created in transit to give the illusion that they did exist. You are the one that invented that history of things according to what you think everything means around you now. I am questioning the sanity of such a position, and simultaneously asking you why you do not have a similar position regarding fossils which could be explained away equally easily.

Originally posted by twhitehead
You are avoiding your previous statement. I am specifically referring to your suggestion that the stars we see never actually existed, and that the light was created in transit to give the illusion that they did exist. You are the one that invented that history of things according to what you think everything means around you now. I am questioning the san ...[text shortened]... u do not have a similar position regarding fossils which could be explained away equally easily.

The light we see is simply the light we see, the stars are there, you jumping
to the conclusions as to how they got there and how long they have been
there is simply that, you thinking you know. I've not invented a history,
I believe one, people who look at stars and come up with possible reasons
why they are there are the one inventing things.
Kelly

Originally posted by KellyJay
The light we see is simply the light we see, the stars are there, you jumping
to the conclusions as to how they got there and how long they have been
there is simply that, you thinking you know. I've not invented a history,
I believe one, people who look at stars and come up with possible reasons
why they are there are the one inventing things.
Kelly

Please try and be clear about this as you seem to be retracting your earlier claim.
Which of the following are true / possible / false?
1. The light was created 'in transit' thus the stars from which the light appears to have come did not exist.
2. The stars do exist and the light we see came from them.
3. There is light and we have no idea whether there are stars.

You seem to be suggesting that the whole field of astronomy is nonsense and a waste of time.

Of course its interesting that the same people who say that the stars exist also said that mars exists and managed to put some robots on it.

Originally posted by twhitehead
Please try and be clear about this as you seem to be retracting your earlier claim.
Which of the following are true / possible / false?
1. The light was created 'in transit' thus the stars from which the light appears to have come did not exist.
2. The stars do exist and the light we see came from them.
3. There is light and we have no idea whether th ...[text shortened]... who say that the stars exist also said that mars exists and managed to put some robots on it.

I believe I was quite clear on what I said.
Kelly

Originally posted by KellyJay
I believe I was quite clear on what I said.
Kelly

I thought you were quite clear too, but then you denied having said what I thought you said, so I am asking for clarification.

You said:
Or when they were created the light stream that would have taken billions of
years was made at the same time,

This to me says that you consider it possible for light to have been created in space in such a way that it looks to us like it is coming from stars.
Is this what you meant or not?