Future of warfare? Creepy drone spins so fast it disappears before your eyes - and could be used to sneak up on the enemy

Hospital staff swapped two babies at birth who were then raised by unsuspecting families... until DNA test 36 years on exposed the scandal, lawsuit alleges Warning to millions as lung-penetrating toxins sweep across 14 US states... with Detroit's air ranked the worst on Earth The detail everyone missed in this photo of Kate and William... and what it reveals about state of their relationship. Scientists at Northwestern University have designed a drone that spins so fast it disappears before your eyes. Called the'Phantom Twist', the drone spins up to 25 times every second, which is too fast for the human eye to see. While it isn't completely invisible, the drone is about 10 times less visible than a conventional quadcopter. Its developers describe its appearance as a'ghostly smudge', claiming it blends'seamlessly into the background'.