Radar image of Asteroid 2003 SD220
© NASA
Radar image of Asteroid 2003 SD220
It's not an Armageddon event, but a huge asteroid made a close approach to Earth early on Saturday showed its curves in a NASA photo session.

Asteroid 2003 SD220 is its official name, but American space scientists called it "hippopotamus wading in a river."

The radar images made by the US space agency's antennas in California, West Virginia and Puerto Rico revealed that the asteroid has an impressive length of at least 1.6 kilometers.

It is very slow with a rotation period of roughly 12 days as it spins like "a poorly thrown football." It's called "non-principal axis" rotation, which is very unusual for near-Earth asteroids, NASA said.

The asteroid will make it slow approach closest to our planet at 1.04am GMT. It'll be separated from Earth by 2.9 million kilometers at that moment.

The asteroid will travel further into space and will only return in 2070, when it will approach Earth slightly closer, but will also pose no real danger.

Three radar images of near-Earth asteroid 2003 SD220
© NASA
Three radar images of near-Earth asteroid 2003 SD220 obtained on Dec. 15-17