June 23, 2002
You are a way for the cosmos to know itself, Carl Sagan once said. On your birthday, the cosmos got to know itself a little better.
Asteroids in the Distance
Birthday · June 23, 2002
A little universe, just for you
Your date.
Ready to give.
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APOD published June 23, 2002. Full image credits are on the original APOD entry below. A publication-date match, not a photo taken on your date. Independent of NASA.
Rocks from space hit Earth every day. The larger the rock, though, the less often Earth is struck. Many kilograms of space dust pitter to Earth daily. Larger bits appear initially as a bright meteor. Baseball-sized rocks and ice-balls streak through our atmosphere daily, most evaporating quickly to nothing. Significant threats do exist for rocks near 100 meters in diameter, which strike the Earth roughly every 1000 years. An object this size could cause significant tidal waves were it to strike an ocean, potentially devastating even distant shores. A collision with a massive asteroid, over 1 km across, is more rare, occurring typically millions of years apart, but could have truly global consequences. Many asteroids remain undiscovered. In fact, one was discovered in 1998 as the long blue streak in the above archival image taken by the Hubble Space Telescope. Last week, the small 100-meter asteroid 2002 MN was discovered only after it whizzed by the Earth, passing well within the orbit of the Moon. 2002 MN passed closer than any asteroid since 1994 XM1. A collision with a large asteroid would not affect Earth's orbit so much as raise dust that would affect Earth's climate. One likely result is a global extinction of many species of life, possibly dwarfing the ongoing extinction occurring now.