Earth-grazing fireball

Frederic Edwin Church, "The Meteor of 1860". 150 years later in 2010 it was determined to be an Earth-grazing meteor procession.^[1]

An Earth-grazing fireball (or Earth-grazer)^[2] is a fireball, a very bright meteor that enters Earth’s atmosphere and leaves again. Some fragments may impact Earth as meteorites, if the meteor starts to break up or explodes in mid-air. These phenomena are then called Earth-grazing meteor processions and bolides.^[1] Famous examples of Earth-grazers are the 1972 Great Daylight Fireball and the Meteor Procession of July 20, 1860.^[1][3][4]

Overview

As an Earth-grazer passes through the atmosphere its mass and velocity are changed, so that its orbit, as it re-enters space, will be different from its orbit as it encountered Earth's atmosphere.^[5][6][7]

There is no agreed-upon end to the upper atmosphere, but rather incrementally thinner air from the stratosphere (~50 km), mesosphere (~85 km), and thermosphere (~690 km) up to the exosphere (~10,000) (see also thermopause). For example, a meteoroid can become a meteor at an altitude of 85–120 km above the Earth.

Known Earth-grazing fireballs

All-sky photo with the Earth-grazing meteoroid of 13 October 1990 (the light track across the picture going from the south to the north) taken at Červená hora (Czechoslovakia), one of the stations of the European Fireball Network. The bright track on the left is the Moon.

An Earth-grazing fireball is a rarely measured kind of fireball^[8] caused by a meteoroid that collides with the Earth but survives the collision by passing through, and exiting, the atmosphere. As of 2008 four grazers have been scientifically observed.^[9]

• Meteor procession of July 20, 1860^[1][3][4]
• Meteor procession of February 9, 1913 led to conclusions a temporary satellite capture of Earth had broken up^[10]
• 1972 Great Daylight Fireball, August 10, 1972, US19720810 at 15 km/s above United States and Canada (first scientific observation).
• October 13, 1990, a 40 kilogram, 41.5 km/s meteoroid passed at 97.9 km above Czechoslovakia (first orbit calculation based on photographic records from two distant places).^[7]
• March 29, 2006, fireball passed 18.8 km/s through the atmosphere 71.4 km above Japan^[11][12]
• August 7, 2007, EN070807 passed through the atmosphere over Europe with an orbit belonging to the rare Aten asteroid type^[8][13]
• June 10, 2012, an Earth-grazing fireball from the Daytime ζ-Perseid shower passed over Spain, travelling 510 km in the atmosphere. It was the faintest Earth-grazing meteor reported in the scientific literature and the first one belonging to a meteor shower.^[14]
• December 24, 2014, a slow moving Christmas Eve fireball SPMN241214 passed over north Africa, Spain and Portugal, travelling about 1,200 km in the atmosphere.^[15]

See also

• List of asteroid close approaches to Earth
• List of Earth-crossing minor planets
• Meteoroid
• Cyrillids

References

External links

Look up Earth-grazing in Wiktionary, the free dictionary.

• Fireball of 1860 (painting)
• Fireball of 1972 (photo)

Modern impact events
On Earth	Pre-2000 1490 Ch'ing-yang 1783 Great Meteor 1860 Great Meteor 1908 Tunguska 1913 Great Meteor Procession 1930 Curuçá River 1938 Chicora meteor 1947 Sikhote-Alin meteorite 1969 Murchison meteorite 1972 Great Daylight Fireball 1990 Earth-grazing meteoroid Post-2000 2002 Eastern Mediterranean 2002 Vitim 2007 Carancas 2008 TC3 impact 2009 Sulawesi superbolide 2012 Sutter's Mill meteorite 2012 UK meteoroid 2012 Novato meteorite 2013 Chelyabinsk meteor Chelyabinsk meteorite 2014 AA impact 2014 Ontario fireball 2015 Kerala meteorite 2015 Thailand bolide WT1190F impact
On Jupiter	1994 Comet Shoemaker–Levy 9 2009 Jupiter impact 2010 Jupiter impact
Lists	Asteroid close approaches to Earth Comets Meteor air bursts Meteorite falls Minor planets crossing Earth's orbit
See also	Asteroid impact avoidance Bolide Earth-grazing fireball Meteor procession Meteor shower Meteorite Meteoroid Near-Earth object Potentially hazardous object