A little asteroid just whizzed by Earth. Not terribly large. Estimates say 20-60 feet long. 2015 HD-1 is one of billions of rocks randomly orbiting the Sun. Tonight it came really close to us.
With asteroids, astronomers calculate the object’s closest distance from Earth and compare that with our distance from the Moon. 2015 HD-1 was only .17 LD (Lunar distances) from our planet. Roughly 40,000 miles.
Astronomers have only known about this interplanetary speck a few days. An automated sky search run by the University of Arizona found it first. It was magnitude 20.1. Very dim.
Sixty feet long isn’t enough to do the Earth in. A sixty footer would probably break up in the atmosphere. Much of it would burn, but plenty of large rocky fragments would fall to earth. And there’d be a destructive sonic boom.
When an asteroid exploded over Siberia a few years it was flying glass from the sonic boom that injured nearly 1,500.
We didn’t know it existed until Saturday. How random is life?