ciprian said:
Interesting.
My problem is how we determine who's accelerating and who's deaccelerating. Without any gravitation involved, then any acceleration or deacceleration will be felt the same way (pushing toward the spaceships walls in one direction or another).
Intuitively the bigger objects are relative stationary to the small ones - Earth vs humans, Sun vs Earth, center of the galaxy vs our Solar System, probably the center of our galaxy supercluster vs Milky Way, etc. So, if I'm changing speed in the opposite direction of the rotation of our Solar System vs center of Milky Way, am I accelerating or deaccelerating?
I assume I'm accelerating vs Sun but deaccelerating vs center of the galaxy... But then how does time dilation apply to me in a theoretical similar scenario?
What you seam to be referring to is simply a matter of perception. In order to see
something moving we compare it against something else.
Let's imagine for example that your spaceship is stationary in space, and that the Earth and
everything else in the universe would be the one accelerating. How much energy do you
think it would take you to do that, even for a little acceleration ? Take for example that it
currently take about the power of about a small town (7 TeV) to accelerate a proton
to near the speed of light 0.999999991 c. Now how you could even accelerate the
universe is a whole other story. Your only other alternative would be a negative
acceleration compare to the universe. Where would an object need to go in order to be
subject to negative acceleration from rest is beyond my current understanding of physic.
The problem I see, is even if our solar system is spinning, it doesn't necessarily has a
big acceleration either negative or positive, it doesn't even have that much speed either
when compared to the speed of light to be honest. Please be careful with speed and
acceleration.
For example, let's say a galaxy is spinning at the speed of 10k Km/h at it extremity. If you
decide to go 10k Km/h in the opposite direction at the extremity of this galaxy you should
be essentially subject to about the same time, since your speed is about the same just in
different direction. If you go even faster let's say 20k Km/h in the opposite direction that
would mean that you would be going 10k Km/h faster then the galaxy.
EDIT : Thanks for pointing that out ghwellsjr.