Time travel light measurement

Discussion in 'Science and Nature' started by thekey2, Jun 5, 2015.

1. How does traveling closer to the speed of light actually slow down time. I've failed to understand this fully. Basically the faster you move toward reaching the speed of light the slower time is experienced for you. One of the analogys I heard was that you are looking at a clock. While you accelerate away from the clock, the light takes longer to reach you and the clock would slow down and would get slower and slower as you neared the speed of light where then the clock would not move at all. However, that is based of human vision, and really the clock has already ticked away, just the light particles havent reached your eye yet to actually show you. How is time not a constant? I know theory of relativity and other theorys have been established in relation to this, im just not sure of specifics. Someone help me out

2. I am not exactly sure but I do know that as you get closer then say you on the ground time slows down. When astronauts come back from the Space Station there clocks are a tiny bit behind. Sats in orbit travel at extreme speeds compared to those on the ground and the software compensates for the time dilation.

I am sure that someone much smarter then myself will explain it but this is something that can be proven in a tangible way.

3. You have this part wrong: "Basically the faster you move toward reaching the speed of light the slower time is experienced for you."

From Wikipedia:

For instance, two rocket ships (A and B) speeding past one another in space would experience time dilation. If they somehow had a clear view into each other's ships, each crew would see the others' clocks and movement as going more slowly. That is, inside the frame of reference of Ship A, everything is moving normally, but everything over on Ship B appears to be moving more slowly (and vice versa).

4. #4
Last edited by a moderator: Jun 5, 2015

Okay but the problem still persists. It "appears" to be moving more slowly. However in actuality time would not be varying, only are perceptions would make us believe as if time has slowed down.  If we had say a camera that could transmit a  video (information) instantly between the ships of the in question clock, would these clock not tick simultaneuous. However when you looked out your window ( of course subjecting any of this was possible ) you would see the time dial moving slower, but is that not an illusion?

5. Looks like this may be due in part of my problem.
• The Principle of Invariant Light Speed - The speed of light is the same in all reference frames and is independent of the velocity of its source
I will have to follow up and report back my findings.

6.
It's not an illusion.  Moving clocks run more slowly as their velocity increases until, at the <a class="">speed of light</a>, they stop running altogether.   There are scientific studies that show this:

From the internet:

A couple of real-life examples may help to make the effects of <a class="">special relativity</a> clearer. Experiments have been carried out where two identical super-accurate atomic clocks were synchronized, and then one was flown around the world on an airplane while the other stayed at home. The clock which travelled recorded marginally less passage of time than the other (as predicted by the <a class="">theory</a>), although the difference was of course minimal due to the relatively slow speeds involved. Our fastest military airplanes can only travel at about 1/300,000 of the of the <a class="">speed of light</a>, so the <a class="">time dilation</a> effect Î³ is only about a ten-thousandth of 1%.

At very high speeds, however, the effect is much more noticeable. Experiments have demonstrated that an ultra-short-lived muon particle, which habitually travels at 99.92% of the <a class="">speed of light</a>, actually lives about 25 times longer and travels about 25 times further than it theoretically should. Particles travelling at speeds up to 99.99% the <a class="">speed of light</a> in the CERN particle accelerator in Switzerland experience the same kind of <a class="">relativity</a>-induced time travel, experiencing a Î³ factor of around 5,000, allowing the artificial persistence of even shorter-lived particles such as phi mesons.

So, if it were possible to travel in a spaceship at, say, 99.5% of the <a class="">speed of light</a>, a hypothetical observer looking in would see the clock moving about 10 times slower than normal and the astronaut inside moving in slow-motion.

7. Space and time are all but one in the same.. as you move through space, you go through changes and that is time. For whatever reason, the faster you move through space.. the less time affects you. It's kind of like walking on a hot beach.. the faster you move, the less it burns. As far as I know with the light speed travel, since less time is affecting you.. your experience will be slow, kind of. Theoretically, if you were to travel at the speed of light.. time wouldn't have an effect on you, but say we hit 99.99% the speed of light.. you'd experience a small amount of time. If you were to travel 50 light years out at 99.99% the speed of light.. the trip would take a lil over 50 Earth years but to you, the trip would of only taken like a minute. Then you travel back to Earth and find that 100 years has passed and youre only a few minutes older than when you left 100 years ago.

8.
And that was the Epiphany that Einstein changed the world with. Its hard to imagine doing things today without computers but back then they would sit around and do thought experiments for hours...literally.

About the best book written on him is the one below. Written by using access to his personal diaries. You walk away from it with the knowledge that Einstein was a deep believer in god, immense imagination, a womanizer, believer in freedom, and by the time he passed we squeezed everything we could out of him. Towards the end he became a recluse because he had become what he hated as a younger person...his mind was closed off to new ideas. Pretty interesting book.

http://www.amazon.com/Einstein-Life-Universe-Walter-Isaacson/dp/0743264746/ref=sr_1_1?ie=UTF8&qid=1433508819&sr=8-1&keywords=einstein

9. #9
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the experiment has actually been done tho to prove it

Atomic clocks put on spacecraft.going at different speeds always show different times relative to eachother and clocks on earth. This is after the clocks are retrieved so its not a perception issue

Not only that but the findings are consistent

We don't know why time dilatation happens. But iits a proven fact that it does

-yuri

10. Okay if none of these answers were what you were looking for I'll throw in another way to look at it. Think of it like this, locally time is constant, but relative to other things it's not.

Example. Imagine you are watching a movie, you and the movie are moving in the same time. Now you fast forward and it looks like they are whizzing around, but if your movie was watching you, it would look like you are in slow motion. You could be moving through time 10times faster than when you were born but you would not know because everything else locally is too.

I'm sorry I'm on break so I couldn't word it all like I would prefer.

Or is your question more "why does time change"

11. the problem is,

When the fast ship and slow ship view into eachothers cameras, they both appear to be moving slower, one is not in fast forward

-yuri

12. how come if you were on a faraway planet for like 3 hours you could've been away from earth for 50 years? is that dependent on the orbital period of the planet?

13. To see why first think of a sound (shock) wave approaching you at 1236 km/h, and let's say you're in a car approaching it at 100 km/h. In the shockwave's reference frame, you pass by it at a speed of 1236 + 100 = 1336 km/h, and this is the same speed by which it passes you by in your inertial reference frame. Time passes by at the same rate for all observers in all reference frames and there are no contractions in space.

Now, with a light wave (ignore quantum effects for now), things become interesting. As you approach it, it does not pass by with a speed of c + your speed, but it passes you by at just c. In your reference frame, you measure the light wave's speed to be c. Preposterous you say, right? How is this even possible? How is that someone clocking 0.75c will measure a light wave to be traveling at exactly c in their reference frame just as someone clocking a measly 100 km/h? This is because time and space transform in exactly such a way as to preserve the constancy of the speed of light in all inertial reference frames. Remember, the velocity v the rate of change of position with respect to time and is a function of both, so both change in every inertial reference frame so that you always measure a light wave to be traveling at c (300,000,000 m/s).

14. The time difference really comes into play when traveling at light speed or near it. Hypothetically, if you were to travel at light speed, you wouldn't really age. Meaning you could travel 1,000 light years at light speed and not age at all.. meanwhile, 1,000 years passed on Earth.

So say there is a planet 25 light years away.. and you travel to it at the speed of light, when you get there you wouldn't have aged at all. Then you spend 3 Earth hours on the planet, and then travel at the speed of light back to Earth.. you'll have aged 3 hours while 50 years and 3 hours passed on Earth. Of course the orbital and rotational speed of the planet would effect the amount you age in comparison to Earth, but it wouldn't be much of a noticeable difference. They say that if an astronaut were to spend 81 years orbiting Earth on the ISS, which is traveling through space faster than if you were on Earth, they only age 80 years.

15. The thing that boggles my mind is the idea that the speed of light is constant from all frames of reference.

This is impossible, because all speed is relative to the movement of 2 things.

But clearly is it possible because we proved it.

To me, this suggests that space and time are mental contructs used to understand energy interactions. Light isn't actually moving at the same speed so much, as it is a fundamental pprocess for the computer of life? Idk

It might also suggest a hidden frame.of reference (like a higgs field)

Think about this. According to the expansion theory, galaxies are moving away from us faster than light. But nothing can move faster than light. And the light escapes at the speed of light always.

So the galaxies appear to.move away from us faster than light because of frame of reference, but to both galaxies light moves at a constant speed.

If space does exist, there has to be some sort of outside frame.of reference

Perhaps light itself is the frame.of reference? Perhaps light doesn't actually "move"

-yuri

16. I have a personal theory that while the speed of light is constant, it's speed relative to us is dictated by the rate of expansion. So if there is a galaxy that is moving away from us at a rate of 100,000 km/s, that means that space around it is also expanding away from us at 100,000 km/s. So that means that light traveling to us from that galaxy is only traveling relative to us at 200,000 km/s instead of 300,000 km/s. While it is still technically traveling at 300,000 km/sec.. it is traveling against expanding space. It'd be like a fish who swims at a constant speed of 10 mph swimming against a current moving at a rate of 9 mph. The fish is still swimming at 10 mph, but only moving forward at a speed of 1 mph. Of course that'd all go against the big bang and the universe's age of 14 billion years.. cause light from a galaxy 13-14 billion light years away would take much much longer than 13-14 billion years to get to us.

17. #17
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I like that, but it brings up another question.

Is not the redshift and blueshift of light caused by its constant speed?

We like to relate the Doppler effect of sound to light, but two very different sciences are involved.

If the speed of light is constant, that would explain why it become stretched toward red as it is emitted by an object moving away; and compressed by an object approaching. If the light simply slowed relative to us, this wouldn't be the case.

-yuri

18. #18
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Actually, it just dawned on me that the expansion of space itself can stretch light, causing all far away light to become more redshifted as it travels over time, regardless of frame of reference.

Even galaxies moving towards us, would have redshifted light if far enough away

Meaning your idea of spacetime itself being the frame of reference might be spot on

-yuri

19. Yeah, that's the conclusion I reached if my theory is accurate.. that light is getting shifted as it leaves the galaxy, the Doppler effect, and then also shifted as it travels through expanding space. But yeah, galaxies whose momentum is carrying towards us can still be redshifted if the rate of expansion is greater than their rate of momentum towards us. That's why we only see blueshifted galaxies close to us.. cause after the rate of expansion relative to us increases, very few galaxies have a momentum toward us to beat out the rate of expansion.

20. Sometimes you refer to time and space seperately and sometimes as one.

If space expands then doesnt time expand too? Thus the frequency of light shouldnt change due to space expanding because the time reference is also expanding. The yardstick is getting longer in lockstep with what its measuring.