[Physicist]

I think I read that as an object approaches the speed of light, it increases in mass. Supposedly one reaches infinite mass at c.

Well, no, because then photons would have infinite mass, but they don't.

And if theorized faster-than-light particles called tachyons exist, why haven't we ever detected Cerenkov radiation in a vacuum?

Because tachyons do not have an electromagnetic charge. Similarly, many neutrinos pass through the air in your room every second at a speed faster than the local speed of light, yet they do no emit Cerenkov radiation.

[scott7278]

Wouldn't there be a problem with "space junk?" It's mind-boggling to think of even a tiny piece of dust slamming into a spaceship at speeds even close to 186,000mps!