Earth got a close shave from an asteroid similar in size to the one that produced the 1908 Tunguska explosion in Siberia. The object, dubbed 2009 DD45, zipped past on March 2 at about twice the distance of geostationary orbit and only days after its discovery. Its orbit intersects Earth’s, but the rock will not get anywhere near this close for another 58 years.
Approximate diameter of 2009 DD45: 35 meters
Speed relative to Earth: 8.82 kilometers per second
Closest approach: 72,200 km
Geosynchronous orbit: 35,786 km
Next near miss: March 2067
Closest approach at that time: 110,682 km
Explosive force that produced the Tunguska damage: 10 to 15 megatons
Number of near-Earth asteroids detected as of March 15, 2009: 6,043
SOURCES: NASA Near Earth Object Program; “The Tunguska Mystery,” by Luca Gasperini et al., in Scientific American; June 2008
