time travel = light speed?

It was once said that if you went at the speed of light you could become your own grandfather, which makes light speed impossible. but if it were possible and we did go speed of light, then we could become our own grandfathers, making us travel through time...wait i dont know where im going with this anymore, could anyone help me out with this?

Schmidt1989

Traveling at the speed of light without manipulating gravity is impossible. If you do manipulate it then no time change will be noticed except the time it takes you to get to where you are going. By creating a gravity distortion you won't experience any G's so you can do all those crazy manuvours. You can also travel many times the speed of light or fly greater distances instantly by other distortions.

oh ok i see. would it be easier to distort gravity on a planet with gravity, like earth, or one without, like the moon...not that its a planet but it doesnt have any gravity.

I believe the theory that speed affects time has been proven as even the clocks on the space shuttle "lose" nanoseconds while in orbit relative to those on the Earth. This means that basically the astronauts come back to Earth minutely younger than if they never left the Earth's surface.

I don't remember the actual amount of time lost at the speed of light but for some reason this figure sticks in my mind: For every year traveling at the speed of light, 40 years are lost. In other words, if you travel away from the Earth at the speed of light for 6 months and then return at the speed of light, every one on Earth will be 40 years older while you'll only have aged 1 year. You don't become your own grandfather but rather you'll be nearly the same age as your children or perhaps even younger.

oh ok it was einstein that said that you become you own grandfather by the way, fogot to mention that in the first post.

Originally posted by Freedom_for_sum
I believe the theory that speed affects time has been proven as even the clocks on the space shuttle "lose" nanoseconds while in orbit relative to those on the Earth....

...I don't remember the actual amount of time lost at the speed of light but for some reason this figure sticks in my mind: For every year traveling at the speed of light, 40 years are lost. In other words, if you travel away from the Earth at the speed of light for 6 months and then return at the speed of light, every one on Earth will be 40 years older while you'll only have aged 1 year.

Actually, it doesn't make much sense to talk about traveling at the speed of light, since that is impossible. But if you were to travel at slightly less than the speed of light for a year, you would lose a little more than 40 years.

The applicable equation that allows you to calculate the number of years "lost" is:

t' = t*sqrt[1-(v/c)^2]

where
t' = time as measured on your vehicle
t = time passing on earth
v = velocity of your vehicle
c = speed of light = 3*10^cm/s; 186,000 mps; 300,000 k/s

when you play with this equation, be sure you use the right units to get the right answer.
An example would be if v/c = .9999 (travel at 99.99% lightspeed) and you kept up this speed for one year, almost 71 years would go by on Earth.

Now for travel at lightspeed.

If you look at the above equation and substitue c for v (as if you went at the speed of light) you can see that no matter how much time went by on earth (t), no time would pass for you (t'). This means if you really did reach lightspeed, you could go anywhere in the universe in no time at all, as measured by your spaceship's clock.

But what if you managed to measure off one second of time on your spaceship while you were traveling at v = c? The equation says:

1 = t*0 (1= your time, t = earth time)

This says that t=1/0, or to interpret it one way, the time passed on Earth would be infinite.

Harte

In Einsteins opinion it's impossibe to travel with the exact sped of light...

Yo, i think going the speed of light is possible, but it may be easier to complete in space. Where their is no stress. has anyone though about how much radiation is in space?

Traveling in a Straight Line going the speed of light will keep you stuck in the present for as long as you travel. Only possible way to go back in time by speed is going faster than light. but then you will only be in the past away from earth... You can't be in the past ON earth. That is until we discover some other way besides light speed travel.

Time travel is all patently ridiculous ... although relativity has pointed out that the rate of perceived time passage can vary depending on other factors like mass and kinetic energy (due to velocity, etc.) time still moves forward ... our physicists' definition of time being able to change scales just means the speed of how fast things happen can vary in certain conditions.

But, it is still moving forward.

It is well know that there are certain events in physics that are reversible, and those that are irreversible.

For example, the birth of a baby is irreversible. How could you possibly unbirth it?

So if you went at the speed of light, you would age at a different speed than your buddy you left on earth does. When you came back to visit, you might find a different Earth, but it would be an older Earth. There is no possible way that you could find a younger Earth, because time marches FORWARD.

Certain processes are reversible, but their sequence is not ... for example, say I melt some ice, and then freeze it again. We can say that the melting of the ice is a reversible process, and that it can be frozen again.

But, the fact that I melted it first, and then froze it again, is irreversible ... the time I did the melting happened first and then the refreezing happened second ... there's just no way to reverse that! We can repeat it, but we cannot and never will be able to, go backwards.

light speed is slow for space travel. i dont think its veasable to become your grandfather at 186000m/ps