People think travelling through space takes a long time. Doesn't the theory of relativity prove it' shorter?

Question

For example, they say we would never be able to live long enough to travel to the nearest star, because it's 2 light years away. But the astronauts only had 1 day of beard growth on there face in 5 days time because of E=MC2, time for them was slower because they were travelling faster. So if you're travelling fast through space, it may take you millions of Earth years, but only 2 space years, right? If I'm wrong then I guess I just proved Einstein wrong.

Answer 1

e = mc² has nothing to do with the time contraction of relativity. You want the Lorentz-Fitzgerald equations (for the simpler special relativity version). How much time contraction you get depends on velocity, and the speed of light is your upper limit. Time may have gone a little slower for the astronauts because of orbital speed, but that's such a small fraction of the speed of light it would take the precision of an atomic clock to notice it -- it would have NO EFFECT on beard growth. What would make a trip to the nearest star (proxima centauri is 4.2 light years away, not 2) take a long time, even for the travellers, is the time it takes to speed up and slow down, assuming known technology.

And no one who says "there face" instead of "their faces" is going to prove Einstein wrong.

Answer 2

Well, let's start with the nearest star not counting the sun, which is actually about 4 light years away. If an astronaut could travel at near light speed, then you would have a point, in that the traveler would not age as much as his friends at home. If he really could approach light speed, then the voyage there and back would take about 10 earth years while he would age a few months.

This has nothing to do with E = mc^2, which deals with the equivalence of mass and energy. Nor does it have anything to do with recent astronauts' facial hair, since they were not traveling at even a tiny fraction of the speeds that you are referring to.

In fact, the technology that you are describing is not currently available. Could be someday, I guess, given unlimited sources of energy, some very hardworking designers, and some astronauts that don't mind extended high acceleration rates. Sorry; you'll have to work a little harder to join Einstein's league, but keep thinking.

Answer 3

Here's the basic problem. Going fast enough.
The fastest man made object EVER, went 241,350 km/h, the Helios 1 & 2 spacecraft in 1974 and 1976.
The fastest a human has ever traveled is only about 16% of that, 39,898.85km/h.
The speed of light, to keep with km/h for consistency, is 1,079,252,850km/h.
Do a calculation, and you see that the fastest a human has ever gone is merely 0.0037% of the speed of light.

Now, check out this little applet:
http://www.pbs.org/wgbh/nova/einstein/hotsciencetwin/
Click on the spaceship, and set the slider over to 10%, then click on the star above the spaceship, a representation of the closest star to our sun (Sol), about 4.2 light years away. Now, going 10% of the speed of light, it still takes a little over 260 years to reach Proxima Centauri. This is why they say we would be dead before reaching there.
At about 50% of the speed of light it takes us about 40 years to get to the closest star (about 47 years would have passed on earth).
When we get to 99.99% of the speed of light (1,079,144,920km/h), it takes the astronaut 1/3 of a year to reach Proxima Centauri while people at home have aged about 27 or so years.
Is all hope lost? Of course not. Things thought impossible 100 years ago now happen daily. In fact, in 1899, the head of the US Patent office said they might as well close down the patent office, as everything that could be invented has already been invented.
Crazy ideas like zero point energy and antigravity research might turn up some things we didn't know existed.

Someone previous mentioned proof. Any satellite in orbit right now uses this theory to keep time correct on the satellite. Even though the time is adjusted by only tiny fractions, they use the time dilation formula to correct the satellites time. This has been standard practice for sometime. There have been many, many experiments to test this theory and it has proven to be true. Here is a link to an answer about proof of Time Dilation.
http://www.physlink.com/Education/AskExperts/ae433.cfm

Answer 4

Only 1 day of beard growth, eh? Would you mind citing a source for that? Even if its true, I doubt it's a result of relativistic time dilation. To reach a ratio of 1 day to 5 days, an object needs to be moving at 98% the speed of light. No made-made object has gone anywhere near that speed. The Apollo spacecraft maxed out at 25,000 mph, which is 0.004% light speed.

Time dilation is a side effect of moving at velocities nearing that of light. Being in outer space has nothing to do with it. Time will not change just because you're in a spaceship.

If an interstellar mission could travel at relativistic speeds, the length of the trip would appear shorter to the crew and long distances could be traversed in their own lifetime. However, accelerating anything bigger than a proton to such speed is impractical. As velocity increases, so does mass and the energy required to accelerate further. It would take an infinite amount of energy to accelerate anything with mass to 100% light speed. We do not have the technology to do it. We probably never will.

Answer 5

You don't understand the theory of relativity (assuming that you mean Einstein's Special Relativity). The main premise underlying all the concepts is that the speed of light is constant regardless of the interaction with the proximity of any mass. Also, Einstein states that "the speed of light in a vacuum is the same for all observers, regardless of their relative motion or of the motion of the source of the light". In other words, even though light will have a gravitational "bend" as it approaches any mass, its speed does not change.
"Earth Time", as you described it, is an invention of man. Our bodies live for a certain amount of time, regardless of how one measures that time. Your beard will grow at different rates based on environmental influences...not because time slowed down...

Answer 6

Einstein's theory demonstrates imagination creates reality. It's really that simple.

With that said, yes, his theory proves time can BOTH be shorter AND longer, simultaneously.

As your species is just now starting to learn with quantum theory, quantum entanglement makes this not just feasible, but simple fact.

Answer 7

totally amazing how people react to "theories". The only way to prove it is to travel out to deep space, say for a year and return. Since we cannot travel at light speed, we cannot prove/disprove relativity. We can travel faster and get more done in smaller amounts of time. But to me, (and if only me) time is the same since (for example) the cesium atom does not change its vibrations and that is what standard time measurement is based on.

Answer 8

that's kind of a misconception about relativity. that time difference happens when you compare time passing on an accelerating spaceship and time passing on earth. but to each person on earth and inside the ship, the same amount of time passes, 10 years is 10 years. it doesn't mean it would only take 5 days to travel the distance, it means that when the astronaut got back after 20 years of travel, less time will have passed on earth, but the astronaut still went through the entire 10 years.

Answer 9

i'm unsure I understand your question. He lit a candle, and then after traveling for hundreds of thousands of years ( assuming he grew to become into traveling on the fee of sunshine) and turning around, traveling a number of extra hundreds of thousands of years, the candle did not get any shorter? It would desire to be a magic candle that doesn't replace after burning for hundreds of thousands of years! that would desire to be some trick!

Answer 10

Time is always on our side whether we are passing thru a black hole or going the speed-o-light, or kissing our best friend's girlfriend. The amount of energy to get from 99% to 99.1% of the speed of light is enormous. Time is always relative. That is, a clock will always be ticking the same time when the clock is with us. If, like you say, we were able to get to the speed of light, then yes Earth will have aged greatly. One side of the equation...earth years... doesn't fractionalize your rocket's clock.