Light Speed Travel in Relevance to Time

[SJeff]

Hello fellows,

I had a question that has been itching me and I have not been able to find an answer too.
Can anyone tell me relative time tables if someone is traveling at the speed of light.
For example: If I travel for 10 year in Light Speed, how many earth years would transpire in real time.
I suppose I can figure it out by doing the math right, but perhaps someone knows of an existing table
or a converter of some sorts. Any help would be appreciated, if not thanks for looking at the thread
anyhow.

Bye.
SJF

[aburt]

Well, it depends how close to the speed of light you get. You can't actually travel at the speed of light (except science fictionally, of course, where you can travel as fast as you'd like, hyperdrive/warp drive/etc. being fairly common).

If you're adhering to Einsteinian relativity, though, then the time dilation equation -- for constant speed -- is, well, easier than trying to do formulas here, check out the section on "Time dilation due to relative velocity" in wikipedia.

Bear in mind that your traveler may also be under acceleration the whole time... (for example, you could provide your traveler with 1g of constant gravity, which would make life comfortable, accelerating at 1g half way, then decelerating at 1g to slow down)... which really complicates the math. See the section on "Time dilation at constant acceleration" in that same article. I worked it out one time and wrote a little Linux script for myself since it isn't pretty.

[Mottman]

i dont think its something that can really be set into a table, there are just so many variables. Gravity being the main one; If your traveller passes through or near any gravity wells on their journey their speed and time is going to be messed up a little. Then there is the fact that Earth is spinning, and moving, and the solar system is spinning and moving as well, this will mess up ALL the calculations. Then position. Will you be measuring time at earth from an orbit or on the surface, because this will, probably significantly, change the end result. Are they travelling away from Earth or towards it? I wonder if that would matter...

[crit19292]

Remember, that Einstein was thinking about a photon moving from a source. Thus, if you move AT the speed of light, time does not change. You stay fixed with the photons that you left with, thus forever stuck with the moment of your achieving light speed.

That is why many do not agree with the time formulas for very fast travels. The problem, however, is that those particles we can propel up to the speed of light (close), OBEYS that law. I once showed up for class only to have the professor not present. He showed up at the next class apologizing, but claiming that he had been in charge of the world's supply of Einsteininium, which normally only had a half-life of so long, but because he had it going at .96 of the speed of light it continued to exist until past time for class. Thus, the present evidence is in support of the formulas for very fast travel.

Now, most consider other laws to become evident when large bodies move to extreme velocities, but we have yet to get there. In my stories, Newtonian physics hold for us. If we go 12 light years at 4 times the speed of light, it takes us three years to get there. It just makes sense, story-wise.