The US Navy Office of Naval Research has just tested its new electromagnetic railgun – a weapon that fires projectiles using only (really strong) magnetic fields.
When operating at maximum power the railgun will fire a projectile 370km at seven times the speed of sound, over 5000 miles per hour.
More video after the jump…
Why does there appear to be a flame trailing behind the projectile – surely if the weapon is electromagnetic, there is no need for propellant?
The flames come from the air resistance between the air and the extremely fast projectile – the extreme heat generated is setting fire to the air itself.
The same effect is seen when high speed spacecraft (re-)enter Earth’s atmosphere.
Apparently the projectiles are initially accelerated by an explosive, which could also explain the effect.