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The minimum orbit intersection distance (MOID) between an asteroid and the Earth is the distance between the closest points of their orbits. This first check is a coarse measure that does not allow an impact prediction to be made, but is based solely on the orbit parameters and gives an initial measure of how close to Earth the asteroid could ...
This is a list of asteroids that have impacted Earth after discovery and orbit calculation that predicted the impact in advance. As of December 2024 [update] , all of the asteroids with predicted impacts were under 5 m (16 ft) in size that were discovered just hours before impact, and burned up in the atmosphere as meteors .
More than one asteroid per year may be listed if its geocentric distance [note 1] is within a tenth of the lunar distance, or 0.10 LD. For comparison, since a satellite in a geostationary orbit has an altitude of about 36,000 km (22,000 mi), then its geocentric distance is 0.11 LD (approximately three times the width of the Earth).
Orbit determination has a long history, beginning with the prehistoric discovery of the planets and subsequent attempts to predict their motions. Johannes Kepler used Tycho Brahe's careful observations of Mars to deduce the elliptical shape of its orbit and its orientation in space, deriving his three laws of planetary motion in the process.
This diagram made available by NASA shows the estimated trajectory of asteroid 2023 BU, in red, affected by the earth's gravity, and the orbit of geosynchronous satellites, in green.
99942 Apophis (provisional designation 2004 MN 4) is a near-Earth asteroid and a potentially hazardous object, 450 metres (1,480 ft) by 170 metres (560 ft) in size, [3] that caused a brief period of concern in December 2004 when initial observations indicated a probability of 2.7% that it would hit Earth on Friday, April 13, 2029.
The asteroid is expected to enter Earth’s orbit Sunday and lurk there until Nov. 25, just over 56 days, Marcos said. Earth as seen from the surface of the moon by the Apollo 11 Command Module in ...
Called a "mini-moon" of sorts by some, it temporarily entered Earth's orbit on Sept. 29 from the Arjuna asteroid belt, which follows a similar orbital path around the sun as the Earth.