and a 12m arm here in long beach, california. and i've been invited to witness a test launch first—hand. now, the 12m accelerator won't be launching into the air — this much smaller projectile be fired down a tube and straight into a steel plate. what happens to this after it's launched from that? so this mostly turns to dust as it hits the end of the tunnel. oh, my gosh. dramatic music. now, where were we? oh, yeah! 500 miles an hour. so now you're going about as fast as a jet. the actual projectiles and the spinning arm are made of carbon fibre — pretty much the only substance that can withstand the forces involved. 700 miles an hour. and in order to spin up to nearly 1000 miles an hour today, this entire chamber needs to be a near vacuum, and that's why we can hardly hear anything.