Um, wow. This video comes from a test firing of the Navys Elecromagnetic Railgun (EMRG), which was carried out yesterday at the Naval Surface Warfare Center in Dahlgren, Virginia. The gun—which generates a powerful electromagnetic field to hurl projectiles at extremely high speeds—is rated at 32 megajoules, but the railgun engineers have to work up to that number slowly: this test was designed to reach a record-setting muzzle energy rating of 10 MJ. (The actual number turned out to be 10.64 MJ, according to Collin Babb with the Office of Naval Research.)

One big question this video begs is, what causes the giant fireball?

Picture this: A massive destroyer receives the location coordinates of an enemy headquarters more than 200 miles away. Instead of launching a million-dollar Tomahawk cruise missile, it points a gun barrel in the direction of the target, diverts electric power from the ship’s engine to the gun turret, and launches a 3-foot-long, 40-pound projectile up a set of superconducting rails.