Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

I would like an answer please.

  1. Jun 27, 2008 #1
    Einstein's special theory of relativity states that if a massive object could reach light speed, then it would be frozen in time compared to an observer who was moving at anything less than the speed of light.

    Time is a dimension in special and general relativity, right?

    Wouldn't traveling at the speed of light make your reality lose the dimension of time?
     
  2. jcsd
  3. Jun 27, 2008 #2

    Hootenanny

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    No, Einstein's Theory of Special Relativity states that a massive object cannot reach C, nor can it tell us what we would see if it were to happen since we are unable to associate an inertial reference frame with something travelling at C.
     
  4. Jun 27, 2008 #3
    But his theories also state that E = mC^2. So hypothetically, you could convert mass to energy, which would then travel at c. You would also have C^2 the amount of energy for the amount of mass. Thus the massenergy of an initially massive object would be traveling at c in wave form.

    The speed of light implies an infinity that cannot be reached but by way of being light.

    On a space voyage, as you get closer and closer to lightspeed, compared to the earth, time for you seems to slow down. A good example of this is the horizontally speeding time clock. If you ever reached light speed, the ratio between the distances traveled from top to bottom on the time clock and from side to side would be the same, so the measured distance of the light beam would be in a ratio to the individual motions, the hypotenuse in the Pythagorean theorem of a right isosceles triangle, the square route of two.

    Of course light cant go the square root of 2 times faster than light. Time has to give. How close do you have to get to light speed for a million earth years to pass in a second for you?

    What percentage of lightspeed would you have to go to have an eternity pass on earth in an instant for you?
     
  5. Jun 27, 2008 #4

    ZapperZ

    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor

    That equation is only a "conversion" factor. When you converted $10 bill into food that you can eat, do you conclude that the $10 bill is edible and tastes as good?

    You should also read the FAQ in the General Physics section on why that equation isn't the whole picture. There's nothing in here that says that an object with a non-zero mass can move exactly at c. A "photon" is not an object with any mass, since its invariant mass is zero.

    It might be helpful if you also figure out how that equation is derived in Special Relativity before you try to make use of it.

    Zz.
     
  6. Jun 27, 2008 #5
    I think you're right in your thinking. If something can slow down, it can stop. I'd like to think about that. Good show.
     
  7. Jun 27, 2008 #6
    Einstein also said that mass and energy were the same thing: massenergy. If a $5 is the same as a hot dog, then yes, it would taste just as good, and would be just as nutritious. The only thing thats different between the $5 and the hotdog is the time it took me to trade them. They are both equal so therefore i can always give up the other to get the other. $5 = the hotdog. The hotdog = $5.

    Therefore the hotdog and the $5 aren't different from each other at all in that they are both equal and could be exchanged with the presence of time.

    What I'm saying is that there's no conversion between mass and energy because its all the same thing, just like space and time. I believe Einstein said this, too.
     
  8. Jun 27, 2008 #7
    And you still haven't answered my question: what percentage light speed would you have to be going for a million years on Earth to pass in one second for you?
     
  9. Jun 27, 2008 #8

    chroot

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Mass and energy are occasionally considered "the same thing," particularly in popular treatments of science. Some have even gone so far as to call mass "frozen energy." Either way, they're still certainly two different phenomena, even if they are in some sense interchangeable.

    Space and time, however, are not interchangeable in any sense at all. Time behaves differently (both mathematically and, of course, in our human experience) than do the spatial dimensions. Just look at the metric signature, for example.

    - Warren
     
  10. Jun 27, 2008 #9

    chroot

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    The ratio between such times is referred to as the Lorentz factor, or often simply 'gamma.'

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

    Can you find a value of u (which is a relative velocity) such that

    [itex]\gamma = \frac{ \textrm{1 million years} }{ \textrm{1 second} }[/itex]

    - Warren
     
  11. Jun 27, 2008 #10

    ZapperZ

    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor

    I wasn't answering your question. I pointed out the mistake you made in using that Einstein's equation.

    Your question is vague. I have no idea who is viewing who's clock where. "a million years on earth to pass in second for you" is strange, because my clock will always be my proper time, and the earth's clock is the one that I see to be slow (since I'm moving relative to earth, I think, in your question). If all you want to calculate is the time dilation where 1 million years in the proper frame has passed when only 1 second has passed in the moving frame, then use the standard time dilation equation

    http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/tdil.html

    and find the ratio of v/c, which is a trivial algebra problem.

    Not sure why this is relevant here.

    Zz.
     
  12. Jun 27, 2008 #11
    "If I pursue a beam of light with the velocity c (velocity of light in a vacuum), I should observe such a beam of light as a spatially oscillatory electromagnetic field at rest. However, there seems to be no such thing, whether on the basis of experience or according to Maxwell's equations. From the very beginning it appeared to me intuitively clear that, judged from the standpoint of such an observer, everything would have to happen according to the same laws as for an observer who, relative to the earth, was at rest. For how, otherwise, should the first observer know, i.e., be able to determine, that he is in a state of fast uniform motion? One sees that in this paradox the germ of the special relativity theory is already contained. Today everyone knows, of course, that all attempts to clarify this paradox satisfactorily were condemned to failure as long as the axiom of the absolute character of time, viz., of a simultaneous, unrecognizedly was anchored in the unconscious. Clearly to recognize this axiom and its arbitrary character really implies already the solution to the problem.''

    Einstein said this. He also said that c is the speed of ultimate motion - you cannot get there because therefore your electromagnetic field would be at rest, which is, by definition, impossible.
    I am not doubting that 4 dimensional matter in space time cannot get to c!

    If you traveled behind a light beam you would see nothing because you need the differences in speed between the light beam and the retina to calculate a 2 dimensional brane.

    For all practicality, light speed and absolute 0 do not exist.

    The reason that I wanted to know if light is 3 dimensional - it carries a 2d projection in time over an indefinable (infinite) distance. So far I only count 3 dimensions - the projection, that's two, and the infinite motion of out - that's 3.

    Even though we must comprehend that it travels at a rate (c) we also know that the rate is a border for our physical reality. Light speed is a false end - the closer you get, the farther away it appears.

    The reason light speed in a vacuum doesn't exist is because there is no such thing as absolute vacuum. Light is obviously slowed down by all the matter around it, so light itself can never travel at c.
     
  13. Jun 27, 2008 #12

    ZapperZ

    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor

    Would you like to give a citation where Einstein actually said this?

    If I show you a hotdog, and I show you a $5 bill, do you see them to be the same thing? They look different, they weigh differently, they even taste different. So how are they the same thing? If I show you a bunch of electrons, can you tell me where they came from? How would you know if they were created out of pair productions, a photoelectric effect, a secondary emission, etc.? Mass and energy are not the same thing. Even their "units" are different. Can they be interchanged under certain conditions? Sure! But try taking 1 unit of energy and see if you can find the identical property of that energy to say that it is also an electron. Simply saying they are the same just because of energy conversion doesn't say anything. You seem to have ignored other properties, such as charge, spin, etc.

    I suggest you do a search on PF. This issue has been discussed already many times.

    Zz.
     
  14. Jun 27, 2008 #13
    How do you separate the existences of space and time? If there was no space to travel, would there be time to travel it? If there was no time, how could you travel through space? Prove to me that they are not interchangeable in the fashion that they need each other to exist.
     
  15. Jun 27, 2008 #14
    Ice looks much different than water, but I know it is the same thing in two different references of time. If I show you the ice cube, and I show you the water, you tell me that the ice cube does not conform to its container. You tell me that the ice cube is lighter than the water. You tell me that the ice cube is much colder than the water. With all these examples, you come to the conclusion that the ice cube is NOT the water. But if you wait around for the ice cube to melt, you will see otherwise.
     
  16. Jun 27, 2008 #15

    ZapperZ

    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor

    OK, since this is physics and not philosophy, can you please show me an experiment that measured the speed of light in our false vacuum and showed that it is below the published value for "c"? Can you also open, say, the standard value of c as published in CODATA and tell me how they were able to obtain that value?

    Zz.
     
  17. Jun 27, 2008 #16

    ZapperZ

    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor

    Ice IS different than water if you go BEYOND the chemical composition! Tell me the crystal structure of water. I can do that for ice.

    Zz.
     
  18. Jun 27, 2008 #17

    chroot

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    We have but one universe, so it's moot to ask questions such as "does space require time to exist?" We have no way of knowing the answers to such questions.

    Either way, it's certainly not correct that space and time are "the same thing" in any respect at all.

    - Warren
     
  19. Jun 27, 2008 #18
    Has anybody made any connections so far that link absolute 0 with light speed. Just as you can never have an electromagnetic wave at rest, you can (apparently) never have matter at rest.

    If you are traveling as fast as the speed of light, (which you can't unless you are light), all other light stays still compared to you and you stay still compared to it. You are motionless compared to a static field.

    At hypothetical light speed, all light appears static.
    At hypothetical absolute zero, does all matter appear static?

    Is there a relationship between these two infinities?
     
  20. Jun 27, 2008 #19
    You still have not shown me why. If they were not the same thing, they could exist without the presence of the other. We see no examples of this, so don't we have to conclude that they are inseparable, and therefore, for all practical purpose, the same entity.
     
  21. Jun 27, 2008 #20

    dx

    User Avatar
    Homework Helper
    Gold Member

    I cannot hear sounds without ears. Are ears and sound the same thing?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: I would like an answer please.
Loading...