the slowdown factor?

Question

When you approch the speed of light, when (percantage wise) will you be traveling twice that of Earth year. AKA one year going that speed would be two years on Earth.

Answer 1

I'm assuming you meant to ask "when (percentage wise) will you be traveling so fast that you experience only one half of the time passed on earth?" Since you are traveling close to the speed of light, time dilation causes the "slowdown effect" so you would never travel "twice that of Earth year." Regardless, travel time is reduced by the inverse of the Lorentz factor, which simplifies to:

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

where v is velocity and c is the speed of light

you are wanting to reduce time by 0.5, thus you would experience half the time a person on Earth experienced so you would set e = 0.5

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

0.25 = 1-v^2/c^2

v^2/c^2 = 0.75

v = 0.866c

Thus, you would need to travel 86.6% the speed of light (c) to experience one half of normal Earth time.

Answer 2

One result of Einstein's theory of special relativity is that a clock on a vehicle moving at high speed will be observed to be ticking slower. Human aging works the same way. Additionally, if you were on the fast vehicle, the rest of the world would seem to be moving in the opposite direction just as fast, and the clocks on the earth would be moving slower.

Time dialation is proportional to the one over the square root of (1-(v/c)^2).
Thus, we want to solve: 2 = 1/(sqrt(1-(v/c)^2). Solving this for v/c, we get v/c=sqrt(3)/2, which comes to abou 86.6% of the speed of light.

Answer 3

Time dilation is what is refered to as slowing down of time.This applies to motion at speed of light. In The daily life on earth motion usually takes place at non speed of light velocities. Humans are not able to travel on earth at these velocities.Hence I cannot give exact answer to light velociies or faster than light velocities travels.