I am imagining two bodies flying through empty space near the speed of light relative to their (distant) surroundings. Let’s say they are a bowling ball and a tennis ball. They are not moving with respect to one another, so their kinetic energy should be zero, yes? And their potential energy would be small. I realize that they have a lot of energy in relation to a wall that gets in their way, but without the wall, there is no kinetic energy in the system, no? But I am told that bodies approaching the speed of light gain huge kinetic energy, and that kinetic energy exerts a gravitational force. If so, wouldn’t the two bodies be able to determine an absolute speed by measuring their gravitational pull? If it is larger than expected, then they have an absolute speedometer. But if their mutual pull appears normal to them, then how can their gravitational pull on each other simultaneously appear extraordinarily high to an observer moving in the opposite direction? (Please understand I am not asking whether a speeding object turns into a black hole.)
Asked
Active
Viewed 78 times
