Nicholas_Bostaph

2003-May-23, 03:55 PM

I have what could be a stupid question related to the speed of light (since I never did have a physics class in HS). I'm just starting to take interest in astronomy again (haven't really thought about it since I was very young) and hope to pick up my first telescope soon :). I've been reading over this board the past few days and find it very educational. Anyway, I started thinking about this scenario the other day and I can't seem to resolve it so it's been really bothering me. Here it is, any thoughts would be appreciated.

If I understand relativity correctly (which I may not) the energy required to accelerate any matter increases exponentially as you approach the speed of light, because relativistic speeds increase the mass of that matter. That's why particles without mass (like photons) can travel at exactly c.

Now, assume that you have two massive bodies, lets say neutron stars for instance, that for some reason are speeding at each other. As they approach, they will begin to exert gravity on one another, which will accelerate them. Now, as they accelerate, they will require more energy to continue the acceleration, but will require that simply because they have more mass due to their velocity. Since the energy accelerating them (gravity) should increase directly proportionally to mass, shouldn't their acceleration continue without end...past the speed of light? Couldn't this also happen if massive binary stars began a decaying orbit of one another?

I've no doubt that I did something wrong in this reasoning, but could someone please tell me what before it drives me crazy :P. Thanks!

If I understand relativity correctly (which I may not) the energy required to accelerate any matter increases exponentially as you approach the speed of light, because relativistic speeds increase the mass of that matter. That's why particles without mass (like photons) can travel at exactly c.

Now, assume that you have two massive bodies, lets say neutron stars for instance, that for some reason are speeding at each other. As they approach, they will begin to exert gravity on one another, which will accelerate them. Now, as they accelerate, they will require more energy to continue the acceleration, but will require that simply because they have more mass due to their velocity. Since the energy accelerating them (gravity) should increase directly proportionally to mass, shouldn't their acceleration continue without end...past the speed of light? Couldn't this also happen if massive binary stars began a decaying orbit of one another?

I've no doubt that I did something wrong in this reasoning, but could someone please tell me what before it drives me crazy :P. Thanks!