Astronomy Picture of the Day

Explanation: Last week, a small asteroid approached unusually close to the Earth. Asteroid 2004 FH posed no danger, but became bright enough to see with binoculars. Passing only 7 Earth radii away, this asteroid pass was the closest yet that was previously predicted, although it was discovered only two days before. Pictured above, the 30-metre sized 2004 FH was imaged from Switzerland crossing the sky on March 18, near its closest approach. The asteroid, centred in the above time-lapse movie covering about 30 minutes, changes in brightness as it tumbles by. An asteroid this size passes this close to Earth about every two years. Were 2004 FH to have struck the Earth, it would have likely burned up in the atmosphere. Large impact features on the Earth are testaments, however, to larger asteroids and comets that actually impacted the Earth in the distant past. Astronomers continue to discover, track, and study potentially hazardous asteroids with a goal of making planet Earth a safer place.