Anonymous
Anonymous asked in Science & MathematicsAstronomy & Space · 1 decade ago

# Question about Time dilation and space flight?

"Time dilation would make it possible for passengers in a fast-moving vehicle to travel further into the future while aging very little, in that their great speed slows down the rate of passage of on-board time. That is, the ship's clock (and according to relativity, any human travelling with it) shows less elapsed time than the clocks of observers on Earth. For sufficiently high speeds the effect is dramatic."

So lets assume im travelling at a constant speed and continue doing so for about a year then decide to come back to earth.what speed would i need to achieve to come back to an earth thats aged by say fifty or a hundred years (in the year that i spent away)

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• Anonymous

absolute crap. The time dialtion effect is relative to the observer on earth, Your ship would appear to have its passage of time slow down to an earth bound observer. If you left with one of two synchronized stopwatches, when you returned to earth, both devices would show the EXACT SAME passage of time REGARDLESS of the speeds your ship obtained.

the way that line shoud read is "the ship's clock... shows (to the observer on EARTH) less elapsed time than the clocks of observers on Earth."

AND the inverse is true... if you are on the ship, looking at earth, the clocks on EARTH appear to slow or stand still... there is no way to "skip ahead" in time... its an OBSERVATION effect only..... Time is an OBJECTIVE reality, not a SUBJECTIVE local phenomenon.

think of a laser beamed away into space and your ship flying along directly next to it... once a second, the laser pulses for 1/100th of a second twice as bright.... a "tick" if you will, at one second intervals... you can observe this "tick" cause you are flying next to the beam... in essence, this "pulse" of extra brigtness is travelling along the beam... at the speed of light.... as your ship gets closer and closer to the speed of light, the slower and slower these "pulses" or ticks catch up to and pass you... eventually, when you reach light speed, you can travell "alongside" one particular pulse. Does this mean time has stopped? for you? on earth? or just "realtive" to your ship and this one particular local phenomenon? if you go just a little bit faster, wont you creep up on and pass previous ticks? does this mean you are travelling back in time? no... beacuse along the total length of this incredibly long laser beam, all the ticks are still moving, at the speed of light, new ones being produced back on earth the whole time. You cant "get back to earth" with out turning around and PASSING by all those other seconds that have been added to the beam behind you... you have NOT "skipped ahead" any... you just caught up to and matched pace with the passing "ticks" of the clock.... the closer you got to "pacing" alongside a tick, the more you APPEARED to slow down to the OBSERVERS back on earth. Even if you could MAGICALLY teleport back to Earth, the time would have passed. Theres no way around it.

Only the massive gravitational field of a black hole can warp time, and thats a one way trip.

• 3 years ago

That is determined by what you imply by means of time. Time as I see it is only whatever that people proposal as much as support give an explanation for the passage of parties and their getting older. I have not heard some thing to contradict the notion that you simply age on the identical cost in house. Well apart from the clinical disorders that could broaden from having no gravity however I actually recognize close to not anything approximately that. And a "day" is simply the time it takes the earth to rotate 360 levels so there aren't any "days" on a flight to mars if you are judging it centered in your place within an area trip. This is all relative as to if or now not you consider time to be a size. Which I don't.

Relativistic effects are measured by a factor which is usually called "gamma" (written with the greek letter), equal to 1/sqrt(1 - v^2/c^2). This quantity is close to 1 when v is a small fraction of the speed of light, and approaches infinity the closer v gets to c.

If you want one of your years to correspond to 100 years on earth, you want a gamma of 100. Solving 1/sqrt(1 - v^2/c^2) = 100 gives

sqrt(1 - v^2/c^2) = 0.01

1 - v^2/c^2 = 0.01^2 = 0.0001

v^2/c^2 = 0.9999

v = sqrt(0.9999) c = 0.99995 c

A gamma of 50 corresponds to v = 0.9998 c