Can Light travel faster than Light?

Discussion in 'General Science & Technology' started by Robittybob1, Dec 3, 2011.

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  1. Robittybob1 Banned Banned

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    Join the club Jim.

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  3. Jim S Registered Senior Member

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    "But same photon is moving away from A at 'c' plus the amount of new space being created."
    I think that sentence has to be wrong - the photon of light will move at c - not plus or minus anything, to all observers.
    On the next question part, I suppose we aren't moving in any direction with respect to the other galaxies, they are all moving away from us - and we are moving away from every one of them. Like dots on a balloon being inflated.
    I've read a lot of books on cosmology, and probably understand 1/4 of it - so I wouldn't be able to argue this stuff to any great extent anyway. It's a darn good thread though, and fun to think about.
     
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  5. Robittybob1 Banned Banned

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    Yes i can understand that. Light is travelling at speed of light in all directions and as long as the galaxy on the other side of the universe isn't going faster than the speed of light light will eventually get there. (Discounting the practicality of this, considering space has a lot of small particles in it which might scatter the light before it actually gets there. Radio waves seem to be quite a lot better at travelling the vast distances.)

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  7. KilljoyKlown Whatever Valued Senior Member

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    I'll bet your not the only one to do that. But you are the only one I've ever met that was willing to say that. Can't say I haven't thought of that too. If you ever run into a guy that goes by the ID of inow, check out some of his responses to religious posts. He has a way of saying how I feel better than I ever could myself. I did ask him how he learned to express himself like that, and he said from years of being in several forums and really working at it.

    It's nice to learn from some of the best scientists in each forum, but be able to express what you learned in your own way.
     
  8. Robittybob1 Banned Banned

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    I enjoy your joke thread too. I make out I'm stupid and create another joke out of that too. I have never written a joke from scratch yet I played a joke (April fools joke) on my boss once and people in the organisation still talk about it.

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    I have never got promoted much. Guess why?

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  9. KilljoyKlown Whatever Valued Senior Member

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    If you are an observer on A and a photon is moving away from you at 'c' and the space between you and the photon is expanding. That means there will be more distance between you and the photon than can be expected if the photon were only moving at the speed of light. So from A's point of view the photon should appear to be moving faster than the speed of light.

    If all the galaxies were in fixed positions, that could be true. However, all galaxies are in motion so it stands to reason we have a direction and whatever that direction is the redshift should be less in the direction we are going and more in the direction we are moving away from.
     
  10. KilljoyKlown Whatever Valued Senior Member

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    I can relate. If you have a family with kids you will have more incentive to advance, and the people you work for will be more apt to give you that chance to advance.
     
  11. Robittybob1 Banned Banned

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    I've got grand kids now, next step is retirement. But I'm going down fighting, I want to come up with something truly scientific. It's not easy to become famous.

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  12. Big Chiller Registered Senior Member

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    The light from the currently farthest visible galaxies were emitted at least 12 billion years ago and it could be that space between those farthest visible galaxies and us have taken a few billion years to accelerate to an expansion rate greater than c meanwhile expanding all along since then, that means it should take a few billion years from now for those farthest visible galaxies to
    move beyond the cosmic horizon from our perspective and longer for galaxies closer to us.

    On another note your post is making me wonder why the photon should never reach B since the photon is moving at c plus the speed of the expanding space through which it travels. Then again what happens when space expanding at the same direction as the photon with the photon traveling through it "overlaps" with space expanding opposite of the photon's direction of travel.


    Maybe we do see less of a redshift in the direction we are moving.
     
    Last edited: Dec 4, 2011
  13. Robittybob1 Banned Banned

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    If you take a little time and look at http://en.wikipedia.org/wiki/Observable_universe you will be amazed by the figures in there and find that things have been moving well over the speed of light for billions of years. To the point I am lost for words, nearly to level where I am saying they are just making it up! But that is just from my naivety, I am but a babe in these discussions. So what the right answer is who knows?
     
  14. KilljoyKlown Whatever Valued Senior Member

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    That would be convenient for those who are pushing that view of reality. But it's almost a certainty that we are not at the middle of the universe and yet we see galaxies at the edge of our ability to see in all directions. So either we are not yet seeing to the cosmic horizon or much of our universe is already beyond it and we should be seeing some galaxies fading out of sight as they cross the horizon.

    If I had to hazard a guess, if the space is really expanding it must be doing so evenly across all space, so that the amount of expansion will always be dependent on the distance one is taking measurements from.

    Maybe, but I've yet to see any documentation or articles on the subject.
     
  15. Big Chiller Registered Senior Member

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    We probably are seeing the galaxies fade out of sight but the process probably takes few billion years.

    Not what I was going for...


    It's probably because as you said space between the galaxies are expanding evenly.
     
  16. dumbest man on earth Real Eyes Realize Real Lies Valued Senior Member

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    Please be patient with me -note my moniker!! Okay, do not fully understand this whole "speed of light" and "age of the universe" as a given! From what my limited mind has been able to "grog" in my lifetime, no one from this planet has ever been more than approximately 250,000 -280,000 miles from this planet. I guess "voyager" is currently traveling through or across the outer boundary of our suns "heliosphere" and is beginning to send data that may or may not tell us what interstellar space may be like. My point being, how can we know that the speed of light is a constant in all parts of the universe? I've been led to believe that there are galaxies that we see at the edge of our "sight" that are so far away that it took more than 13 billion years for the light from them to reach us. If they were that far away from us 13 billion years ago and the age of the universe is 13.7 to 14 billion years old - it seems to me (remember my moniker!!) that somewhere or somehow at sometime, something must have been moving or expanding faster than our understanding of "speed of light". If I am not wrong - again, my moniker - then either the universe "began" quite large (no "Big Bang") or our knowledge is highly overrated. Personally, I believe that we have yet to graduate even kindergarten in the greater academia of "universal knowledge". I have heard that there are people who "Don't Know Anything". I have learned that there are people who "Don't Even Suspect Anything". As for myself, I am trying to be able to suspect some of it! So;Can Light travel faster than Light? I suspect......yes, relative to MY current non-understanding!!!!
     
  17. hardalee Registered Senior Member

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    Sorry, I had to go to a holliday party.

    In that time, this post has lost all relaiton to reality.

    Have fun with it.

    Bye.
     
  18. KilljoyKlown Whatever Valued Senior Member

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    In another 5 or 6 years some of the next generation Very large telescopes will be coming online. For anybody interested I did a topic on that subject. That should help with the cosmic horizon questions.

    Yeah I know, but maybe you could clarify what you were going for a bit more. But let me ask this question. If the space that light is traveling through is expanding, wouldn't that mean light is taking longer to get here and if it does take longer to get here that would mean the universe is younger than previously thought. Unless expanding space was included in the calculation that produced our 13.7 billion year age of the universe.

    That's not quite what I said. I said if space is really expanding that it would have to be expanding evenly across all space. I meant as opposed to expanding only in between galaxies or clusters of galaxies. but then I'm not very convinced the expansion is taking place as has been described.
     
  19. KilljoyKlown Whatever Valued Senior Member

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    I like your attitude, but I suspect your aren't really the dumbest man on earth. I wonder if you can find an avatar in tune with your ID.

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    I once read somewhere that time and space are varible so that 'c' will remain constant. I find that concept hard to grasp. What do you think and welcome to the forum.
     
  20. kwhilborn Banned Banned

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    Killjoyklown is wrong as he is not looking at the increase in the measuring device.
    Einstein would look at the target universe from the position of the light itself, and will catch anything going only half the speed of light. If it is just the things like planets that were drifting apart, but that's not what is happening.

    I think this answer is misleading because it leaves out the expansion of the universe (which is relative to the question). However because the measuring devices we have for distance and speed also expand equally this statement is also unfortunately correct. Am I making sense?

    This is why it can get confusing.

    Are things drifting away from each other or is the space between objects also growing.

    Once the light has left a star in one of the posed Halves, the distance it must travel would be increasing more than the speed of the opposite universe. This might not make much sense unless you imagine that if you were using a ruler or yardstick somewhere in random space that yardstick would need to grow like a plant the atoms within our measuring device and we ourselves grow at the same expansion rate.

    This is where Killjoyclowns answer becomes fuzzy, as it is theoretically possible for this space to increase faster than light can travel, but that is not true at the moment.

    If space were expanding faster than the speed of light we would still see the distant objects but time would be running backwards on them.

    If we could launch a mirror at the speed of light and see clearly through it any given spot on our planet we could watch our own history. Similar to what we would view from the other half of the universe in this scenario if the speeds were doubled.

    This is a confusing subject, and there are different views on how to interpret results. I think the balloon metaphor is the most common, but you must imagine the space inside the balloon increasing in size (like a yardstick), and not concentrate on the balloon itself.

    So now imagine a light has left our planet to the other planet travelling at the speed of light. From its perspective it may seem to think it is going slower than the speed of light as the "road/yardstick" increases, but for the same reason does not notice as it is also gaining speed based on the expansion of itself. From our perspective on earth, the light would have travelled the distance over time based on the speed of light, but also the increased distance of the universes internal expansion (if we could see it. So would this make it appear light has travelled farther than light could hence faster? Anyone? killjoyklown?

    (I apologize if I read you wrong but think this is where killjoyklown was mistaken, it is not to do with relativity and measurement. The measuring devices also change.)

    No, because we must also increase our yardstick. Yes. because it has travelled farther hence faster than the speed of light via expansion. Does that make sense? No is the real answer imho.

    Logically you would think that we ourselves must be expanding with this thinking. Atoms themselves must be expanding. This is a strong subject of debate, but It's not that stars and galaxies are getting bigger; rather, the space between all objects is expanding with time.

    It is this spatial expansion that leads us to think of a point in time when there was no distances between all atoms. This makes us think of the separation/BIG BANG.

    Controversy, controversy. Semantics. Yeesh!

    Here is the best answers for that subject.
    http://van.physics.illinois.edu/qa/listing.php?id=1120

    How could we notice if our yardstick is also growing, and everything looks to be in place?
    However Hubble proved him right when he observed the light coming from all distances displayed a growth shift .

    This is all based on the BIG BANG theory being correct.

    good website i found that quote
    http://skyserver.sdss.org/dr1/en/proj/basic/universe/

    Light is always faster than the speed of light, but the distance we use to measure it also expands so it appears normal.
     
    Last edited: Dec 4, 2011
  21. AlexG Like nailing Jello to a tree Valued Senior Member

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    Soneone else who misunderstands what the BB is and spatial expansion does.
     
  22. kwhilborn Banned Banned

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    How so? I think I have it down pretty good, or are you referring to someone else?. I'm open for correction. I think I have had a firmer grasp on this than many people. I may have explained something poorly, but if you read the entire post you will see I understand it perfectly.

    For the record, I think I did a pretty good job of explaining it as well, but wish I could rewrite to make it a bit clearer.
     
  23. Robittybob1 Banned Banned

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    Come on then Alex spill the beans.

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