Suppose you're traveling on a space ship at 9/10 the speed of light (.9c). You have a high-powered rifle that shoots bullets at the same speed. Suppose you shoot the bullet perpendicular to your direction of travel.
It appears that the bullet would travel at a 45-degree angle (northeast, if the ship is traveling north and the bullet is shot eastward), at about 1.2728c which is faster than light. Why is this wrong, and what would the actual speed and direction be?
(In reply to
No Subject by nilshady)
Neither of your assertions is true, nilshady.
(1) Accelerating at the rate of 1g (32 ft/sec/sec) you'd reach 9/10 c
in a little less than a year (not counting the time slow-down due to
relativity). This time slow-down is 43.59% at 9/10c (as Jay
showed). Allowing for this, you'd still be able to reach 9/10 c
in less than 2 years. So, the person might get awfully bored, but
shouldn't die.
(2) There's no reason the ship would burn up, unless it ran into
something. In outer space there's no air to cause friction to
cause heat.