On Feb. 2, a large asteroid safely drifted past Earth at a distance of about 1.8 million miles (2.9 million kilometers, or 7 0.5 times the distance between Earth and the Moon). There was no risk of the asteroid - called 2008 OS7 - impacting our planet, but scientists at NASA's Jet Propulsion Laboratory in Southern California used a powerful radio antenna to better determine the size, rotation,
