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Archive:Earth-impact events

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Revision as of 01:41, 17 October 2008 by wikademia>Mu301 (+img)

Near-Earth objects (NEO) are asteroids, comets and large meteoroids whose orbits bring them close to Earth's orbit, and which may therefore pose a collision danger.

On October 7, 2008 a meteoroid called 2008 TC3 which was 2 to 5 meters (7 to 16 ft) in diameter entered Earth's atmosphere and burned up before it reached the ground. The object had just been discovered about a day before the impact. It exploded tens of kilometers above the ground with the energy of around one kiloton of TNT, causing a large fireball in the early morning sky over northern Sudan.

Radar image of 4179 Toutatis

Potentially Hazardous Asteroids (PHA) are Near-Earth asteroids that are big enough to cause unprecedented regional devastation if they were to hit the Earth.

On September 29, 2004 the asteroid 4179 Toutatis made a particularly close approach (within 4 LD, or lunar distances) from Earth. The next close approach is November 9, 2008, but it will be five times more distant. It is about 4.6 km by 2.4 km in size.

There is some concern that the asteroid 99942 Apophis could impact earth on April 13, 2036. The probability of a collision is currently esitmated to be 1 in 45,000. These calculations are uncertain due to another close encounter in 2029 which could modify the orbit of the asteroid, making a collision either more or less likely.

NEO Earth Close-Approaches

  • 2008 TN9 (unknown diameter) on 2008-Oct-03 miss distance of 0.6 LD
  • 2008 TS26 (about 1 m) on 2008-Oct-09 miss distance of 0.03 LD
  • 2008 TT26 (49 m - 110 m) on 2008-Oct-23 miss distance of 3.6 LD
  • 2005 VN (72 m - 160 m) on 2008-Oct-29 miss distance of 4.1 LD

PHA Earth Close-Approaches

  • 1999 AQ10 (240 m - 540 m) on 2009-Feb-18 miss distance of 4.4 LD

See the NASA/JPL Near Earth Object Program for up-to-date information.

In the news

See also