A google search revealed an often asked question (including a locked thread here) about two ships approaching with closing speed > c, say each going .75c. And there's always multiple answers from the experts about relative frames and Lorentz this and that and you have to use the special formula etc. I get that the spaceship measures the speed of the other spaceship at some speed less than c given by whatever that formula is, I won't argue that (well I don't TRULY get it, but I won't attempt to refute it). My question though, is what if the spaceships are rigged with superpowerful airbags and other safety devices such that the collision at the speed they measure the incoming spaceship at gives it a kinetic energy below the threshold of immediate death? What about the earth observer that sees them crashing with a KE = 1/2 * m * .75c^2 per ship? The earth guy knows they are going too fast for the safety equipment and correctly predicts they die... But on the ship they correctly predict the equipment will save them? Well they either die or don't as if they actually didn't they would fly back and talk to the guy on earth and call him crazy... All I can think of is that the KE is increased by the m factor... apparently the incoming ship is not merely going faster but it has somehow e.g. quadrupled in size or density? The second sort of paradox I have is a variation on the barn and pole paradox: http://math.ucr.edu/home/baez/physics/Relativity/SR/barn_pole.html What happens if the barn has the doors removed and is rigged with a laser "trip wire" in each open doorway, such that if the trip wires are both cut, a bomb goes off? Let's presume that the contraction makes the pole just barely fit from the stationary observer's perspective. The stationary observer thus watches the runner safely pass through the barn. The runner unfortunately watches the pole pass through the rear laser, breaking line of sight with the detector at least until the front of the pole breaks LOS on the second laser and detector, so both lasers are cut and the bomb goes off. The paradox in the link talks about how the doors didn't close and open at the same time from the runner's point of view, which I can accept, and therefore the runner never smashed into one of them. But what happens in this case where the "doors" (trip wires) are required to remain "closed" (not cut)? In the original version, the front door closes to the runner's view, the pole gets to it, it opens, the pole passes far enough through that the rear door can then barely close, then the rear door opens. But the pole did actually pass through a very small barn, even if the when of the doors closing is disagreed upon. So just change the *temporary* door closing idea with a *permanent* requirement to not have two broken lasers at ANY POINT... The runner breaks both lasers at some point from their point of view, even though individually they broke at different times and at different times from when the guy on the roof saw them break (and he didn't even know they were both broken... until the bomb goes off).