Your home planet moves at .75c relative to the center of the galaxy, you build a spaceship that can decelerate to stationary relative to the galaxy and then accelerate again to .75c. You take off and accelerate in the opposite direction of your planet's movement.
How fast does someone observing you from your home planet perceive you to be moving? according to Einstein's theory about .625c
however...
How much do you appear to have accelerated from the perspective of someone stationary relative to the galaxy?
How fast do you perceive yourself to be moving relative to your planet?
>>8165369
Problem. By "opposite direction", do we mean rotational or linear in respect to the center of the galaxy?
>>8165453
assume the galaxy is so big that the curve is negligible
bout tree fiddy
>>8165369
1.5c.
What you drew in the picture is the answer to your first question. A 'galaxy fixed' observer will observe them moving away from each other at 0.75c. That's how the problem is explained.
The perceived speed relative to your planet when attaching the reference frame to a moving frame (the rocket ship), a simple Galilean transformation for such relativistic speeds. That is to say you cannot simply add V1 and V2. You must then take into account whats called a lorentz factor, which will normalize the speed such that C is asymptotic. I'll let you do the math, but its a number higher than 0.75C and lower than 1.0C
>>8165520
***... simple Galilean transformation for such relativistic speeds [is inadequate].
>>8165581
fuck off fag, I'm just looking for good discussion
I think there's a problem in the axioms here, from the static perspective you aren't observing a stationary object accelerate to 1.5c you're watching an object going .75c decelerate and then accelerate again
general relativity will probably slow that down to like .4c or something though
>>8166257
so from one perspective you could say it accelerated to 1.5c?
>>8166229
There is no room for discussion here.
If you knew anything about special relativity you would not be asking these questions.
