Who would have thought that monkeying with space/time for fun and profit would have negative consequences?
Okay guys, so, like, space? It's really big. Like, really big. Seriously. And despite mankind's intense desire to explore new planets and have ill-advised sexy time with whatever we find there, it's just not terribly feasible with our current propulsion technology. Even a trip to Mars, the nearest planet in our solar system, would take over 200 days, and that's barring any sort of xenomorph infestation, or giant space babies attempting to expand man's collective consciousness.
Thus "faster than light" travel has become a staple of space-based science fiction. Can you even imagine Star Trek without the Enterprise's warp drive? Actually, let's hope so, because according to a group of Australian scientists, that kind of technology would more or less destroy everything.
The University of Sydney-based group studied the theoretical Alcubierre drive -- in simple terms, it moves a ship through space by "creating a bubble of negative energy around it, expanding space (and time) behind the ship while compressing space in front of it" -- and determined that though it's should be possible to break the lightspeed barrier, the problems start once you attempt to stop.
See, that negative energy bubble functions much like a wave in the ocean. As your ship is propelled along, the bubble is also picking up random detritus (in the ocean it would be sand and sea urchins, but in space it's incredibly tiny particles). When you attempt to come to a stop, all of that extra stuff you've accumulated still has momentum and will continue forward. End result: Billions of tiny, tiny particles being flung through space at speeds faster than light to collide with whatever might be sitting at your destination.
"Any people at the destination would be gamma ray and high energy particle blasted into oblivion due to the extreme blueshifts for [forward] region particles," the team's paper states.
Interestingly (for maniacal supervillains, at least), there doesn't seem to be any upper limit to exactly how destructive this burst can be. Thanks to a quirk of General Relativity, you can continue accumulating energy as long as you stay in that negative energy bubble. You only lose energy when you stop, at which point, again, things go boom.
Now, in fairness, this is all based on a completely theoretical faster than light drive, and even generating that negative energy bubble would require technology we can only dream of, but I'd like to posit the idea that though the warp drive might not be a great method of travel, it would make a really awesome interstellar weapon.
Who needs to drop a comet on a your foes when you could hit them with a superluminal grapeshot burst of weaponized protons?