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RE: Space travel to the end of the universe… and back

in #science7 years ago

We obtain that the one-way trip to the end of the universe will last slightly more than 47.5 years!

I thought to myself "Well, if there was a spaceship which could do the job i would certainly go to see the edge of the universe" - That would be cool.
But there is something that isn't clear to me, if the universe is expanding in every direction (given any point) faster than light, how does the spaceship arrive at the edge of the universe? Or am I wrong?

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But there is something that isn't clear to me, if the universe is expanding in every direction (given any point) faster than light, how does the spaceship arrive at the edge of the universe? Or am I wrong?

You got the imprecision with the calculation. Congratulations! We should say, the limit of the universe today ;)

Actually, saying that the expansion of the universe is faster than light is a bit misleading, as velocities as such have no meaning in this context of very distant objects (in short, the entire concept of velocity is local).

You got the imprecision with the calculation. Congratulations!

Yay! Even if that wasn't the intention :-)

the entire concept of velocity is local

Absolutely true. But my doubt is:

Given that the universe is "stretching" at about 68 km/s per megaparsec, it means to me that, considering the earth as the center of the universe (or at least, of the observable universe), for each megaparsec in a given direction i should add ~68km/s until i reach a distance where there is a point which is "moving faster" than light (from the earth prospective) and that i can't reach at the speed of light.

Isn't that right?

Or is the movement of that point just apparent given my position on earth?

P.S. I know Imay sound petulant asking these questions, but hey... free physics lessons :-)

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