How did Einstein discover that if you travel the speed of light that time slows down?

Question

Also why would this happen? i cant understand how going really really fast can slow down time (for you only?) (is it your ageing slows down or will acualy go back in time?) compared to others not going so fast.

Answer 1

He sat at his desk with a pencil and paper, thought about it, and did some calculations. I understand he had a lot of free time in his job as a patent clerk.

Now, I'll admit that you or I would have never thought of this, even if we had all the free time in the would. Einstein's brain was definitely wired different from the rest of us.

Answer 2

First he didn't 'discover' it - he formed a Theory (which others have since proved to be correct).

Next, no physical object (i.e.one with Mass > 0) can actually travel at the speed of light = it's not just a matter of 'belief' (it's wired into the Equations that form part of the Theory), and yes, Photons do travel at the speed of light, but then photons have no mass.

However you are correct in saying that the 'faster you go', the more time slows down (for you, only) RELATIVE to the rest of the Universe.

.. and yes, time does indeed slow down .. it's not just that you will age slower, EVERYTHING will be running slower for you - you will not be able to dicover any difference because time will have slowed down ... all the measurements you make will continue to show that everything is 'OK' (for you)

NB. Ignoring (for the moment) Theories involving Exotic Matter (or infinite cylinders rotating at light speed), it's impossible to "go back in time " (see 'Causality')

Answer 3

Einstein figured it out in his thoughts. It wasn't proven until many years later.

The only way I could get my mind around the concept of time slowing down was to think of how speed is measured. It has a distance component and a time component. Also, thinking of space/time always moving at the speed of light. This is easy to think when you sit down without seeming to move through space with time ticking away the same as always. It is much harder to imagine the other way when you are moving near the speed of light and time is slowing down.

What happens to your own sense of time when traveling near the speed of light is that time is ticking away the same as always. But when you return to earth, much more time has gone by on earth and if you were traveling for very long, everyone you knew would be gone. This has been tested with clocks being sent off as fast as possible & then compared with clocks remaining on earth. The fast traveling clocks tick off less time than the more stationary ones.

Anyway, the whole idea is counter-intuitive and takes a lot of thinking to even get to my level of understanding which is a lay person who reads a lot of science books.

Answer 4

If you were able to travel at light speed and you travelled out and back at that speed for 14 of your earth years then in theory 100 of everyone back homes earth years would have passed.Time is relative,space infinite,light speed constant (unless bent around huge gravitational masses) Einstein had good sense. If you travel past a speed camera fast enough it will get a photo of nothing (well not of your vehicle) Time space speed. If a car travels at 40mph and a bike at 100mph who will get there first? How much time will the biker of saved? Now try this at light speed vs life cycle/time on earth.I am certain you have more eloquent and scientific answers above and below.(Certain cultures beliefs encourage ideas of time travel and we are obsessed with time , so sooner or later we will figure out everything we desperately need to know! )

Answer 5

Einsteins theory states that it is impossible for physical objects to travel AT the speed of light (or faster). He did do what he called "thought experiments" to show approaching the speed of light has this effect. I believe he called it time dilation. I understand it happens with fast moving objects, like shuttles, but the effect is so tiny, it would take centuries to notice the difference, even if you use accurate timepieces like atomic clocks.

Answer 6

It comes from a thing called the Lorents transform and is a result of the fact that no matter how you are moving, the speed of light is always the same. The only way for that to be true is to adjust thelength or time that you measure. The Lorentz ytransform met that need.

Answer 7

Light is the fastest thing known to man. Travelling at the speed of light or beyond the speed of light would mean that you would be travelling faster than time itself, therefore time would slow down and ultimately cease.

Answer 8

May be Einstein believed that you cannot travel faster than Time.
On that note it can be said that nothing can travel faster than time.
So Even if you traveled at the speed of light it would make no sense that time is moving slower than your motion.Because its just not real.
However if you assume an imaginary quantity to time ,then its a different mathematical game.

Answer 9

He did not so much discover it as predict its discovery. During the 19th century, there were efforts going on to figure out what the medium was that light passed through. Einstein had the foresight to picture himself riding along with the light beam. His real insight (at least in this matter) was that the speed of light is constant and independent of the motion of the source or the observer. The Michelson-Morley experiment results demonstrated this, although it is not clear that Einstein knew about it at the time. Now think about what that means. If you are traveling toward a star at 90% of the speed of light, then the light from that star still passes you at the exact speed of light RELATIVE TO YOU. If a star is receding from us at 50% of the speed of light (as many of them are) then the light from that star still reaches us going exactly the same speed ( ~186,00 miles / sec). We have seen that this is indeed true through countless measurements. Now what does this do to time? Well, not much until you are traveling at near light speed. Imagine yourself standing on an asteroid watching a friend pass by at near light speed in a spaceship made of glass. As he passes you, he shines a flashlight at the floor of his ship. In his ship, he sees the photons in the light beam travel straight down and then reflect straight back up to his eye from the glass floor. But what you see is different. You see the photons travel down at an angle, hit the floor, and then angle back up due the relative speed of the ship. Therefore, the path that the photons take is longer when measured in your frame of reference than it is when measured in your friend's frame of reference riding along in the ship. It is important to note that neither of you has the "correct" measurement. It is only correct as measured in your world vs. his world. There is one more step to get to time dilation. Since your measured path of the light beam is longer, and since the speed of light is constant (regardless of the observer or the source), then we can think of this as a simple distance = rate x time problem. Since the speed (or rate) is constant, and since the distance is longer, then the time must change in one frame as seen by the other. It takes the normal amount of time for your friend to see the photons bounce up from the floor, but on your asteroid, the event takes longer. It doesn't just appear to take longer, it really takes longer. The time dilation resulting from this is completely predictable per the Lorentz Transform equations. Time and distance (space) are tied together and are relative. The speed of light is constant. At least that's what we think today. Hope this helps.

Answer 10

Einstein was one smart MoFo for sure. He did a lot of thought experiments, and was a genius!

Look outside tonight at a star...that light has been traveling for many, many years to get to us. But if you happened to live on that star you would not notice that.

Check out this link for more: http://www.pbs.org/wgbh/nova/einstein/relativity/