"Dirk Van de moortel" wrote in message
...
Martin Hogbin wrote in message

wrote in message ...
Hello again,

Assume I take a spaceship to Alpha Centauri, which is 4 light years
away. And the ship goes so fast, that the travel time seems to me to
be one hour. Will it not seem to me that Alpha Centauri made a journey
that started at x=4[ly] and ended at x=0, during a time of one hour,
and therefore its speed was much faster than lightspeed? Where is my
mistake?

Does anyone know the name of the speed calculated by ram?

Coordinate distance over proper time.
I think it is called "proper velocity", or in this case "proper speed"

Thanks, that is what I was looking for. I quick Google search
shows that you are correct. Curious name, though..
--
Martin Hogbin