Officially dubbed Asteroid(52768) 1998 O2, the space rock came within 3.9 million miles (6.29 million km) of Earth at its closest today - that is about 16 times farther than the Moon is. Asteroid OR2 is one of many so-called near-Earth objects (NEOs) that orbit the Sun within 1.3 astronomical units (au) or 120.8 million miles (194.4 million km). Dozens of asteroids make close approaches each month and NASAtracks their orbits if they come within five million miles of Earth.