The Air Force just successfully tested an $8.1 billion 'nuclear gravity bomb'

A jet fighter dropped an unarmed "nuclear gravity bomb" in a Nevada desert test range on October 20.

While this might sound like Earth-shattering news, a gravity bomb is not a futuristic weapons technology brought to Earth by aliens.

Instead, a gravity bomb is just that: A bomb powered by gravity. You lug one into the air, drop it, and hope the force of gravity pulls it down to the spot that you've targeted.

The gravity bomb in this case is called a B61-12, and it's designed by the National Nuclear Security Administration (NNSA) and Sandia Labs and able to carry nuclear explosives.

But it's not different from bombs that humankind has dropped on itself for decades. Soldiers sometimes call them "dumb" bombs because there is no GPS guidance or rocket propulsion - just tail fins to help guide the bomb through the air toward its target.

Keep scrolling to see why the US government is spending $8.1 billion to design and test the B61-12.