Not all rockets travel up. Some go sideways. On Mythbusters, Jamie Hyneman and My Close Personal Friend Adam Savage™ were testing whether a head-on collision of two semis could fuse the metal together. That didn't work, so they took the next logical step: using a rocket sled to slam into a car, ramming into a one-inch thick piece of plate metal behind it. What followed may be the single greatest thing ever aired on television ever. Holy crap! The sled had two stages; the first burned for only a second or two, then the second stage ignited. This gives the sled a lot more speed; the first stage has to push on the whole sled, accelerating it, but the second stage only has to push on about half the mass, and the acceleration is much higher. The impact was at well over 600 miles per hour! You can see the second stage hit first, then the slower moving (but still screaming fast) first stage catches up a second later. Here's another (awesome) angle: Whoa. If you saw the episode you know what happened: the car and the metal plate didn't fuse, but the car was torn literally to shreds, and the inch-thick plate metal was bent like it was warm taffy. Since they didn't fuse, I'll have to grant that one a "Busted"; the energy per unit mass of the impact was probably 20-30 times that of a head-on collision between trucks, so if that didn't do it, not much else will. Wanna see it in super slo-mo? Heh. On the Discovery site is a page where you can scan through that high-speed footage frame by frame, too. One of these days I'm gonna have to tag along with these guys when they film. Wow.