A strewn field is the area where meteorites from a single fall are dispersed. [1] It is also often used for the area containing tektites produced by large meteorite impact. [2]
A strewn field is the area where meteorites from a single fall are dispersed. [1] It is also often used for the area containing tektites produced by large meteorite impact. [2]
 | This section includes a list of general references, but it lacks sufficient corresponding inline citations .(March 2024) |
There are two strewnfield formation mechanisms:
| This section includes a list of general references, but it lacks sufficient corresponding inline citations .(March 2024) |
In the case of mid-air fragmentation, smaller fragments tend to fall shorter and the biggest fragments are usually found at the far end of the oval. In order to get an idea of the original flight direction it is necessary to analyze the size pattern of the material over the strewnfield. Fragments of about 1 to 5 grams can be picked up on weather radar as they fall at terminal velocity.
An impact crater is a circular depression in the surface of a solid astronomical object formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact craters typically have raised rims and floors that are lower in elevation than the surrounding terrain. Lunar impact craters range from microscopic craters on lunar rocks returned by the Apollo program and small, simple, bowl-shaped depressions in the lunar regolith to large, complex, multi-ringed impact basins. Meteor Crater is a well-known example of a small impact crater on Earth.
A meteorite is a solid piece of debris from an object, such as a comet, asteroid, or meteoroid, that originates in outer space and survives its passage through the atmosphere to reach the surface of a planet or moon. When the original object enters the atmosphere, various factors such as friction, pressure, and chemical interactions with the atmospheric gases cause it to heat up and radiate energy. It then becomes a meteor and forms a fireball, also known as a shooting star; astronomers call the brightest examples "bolides". Once it settles on the larger body's surface, the meteor becomes a meteorite. Meteorites vary greatly in size. For geologists, a bolide is a meteorite large enough to create an impact crater.
The Tunguska event was a 3–5 megaton explosion that occurred near the Podkamennaya Tunguska River in Yeniseysk Governorate, Russia, on the morning of 30 June 1908. The explosion over the sparsely populated East Siberian taiga flattened an estimated 80 million trees over an area of 2,150 km2 (830 sq mi) of forest, and eyewitness accounts suggest up to three people may have died. The explosion is generally attributed to a meteor air burst, the atmospheric explosion of a stony asteroid about 50–60 metres wide. The asteroid approached from the east-south-east, probably with a relatively high speed of about 27 km/s (60,000 mph). Though the incident is classified as an impact event, the object is thought to have exploded at an altitude of 5 to 10 kilometres rather than hitting the Earth's surface, leaving no impact crater.
A meteoroid is a small rocky or metallic body in outer space. Meteoroids are distinguished as objects significantly smaller than asteroids, ranging in size from grains to objects up to a meter wide. Objects smaller than meteoroids are classified as micrometeoroids or space dust. Most are fragments from comets or asteroids, whereas others are collision impact debris ejected from bodies such as the Moon or Mars.
Tektites are gravel-sized bodies composed of black, green, brown or grey natural glass formed from terrestrial debris ejected during meteorite impacts. The term was coined by Austrian geologist Franz Eduard Suess (1867–1941), son of Eduard Suess. They generally range in size from millimetres to centimetres. Millimetre-scale tektites are known as microtektites.
An iron meteorite fell on the Sikhote-Alin Mountains, in southeastern Russia, in 1947. Large iron meteorite falls have been witnessed and fragments recovered but never before, in recorded history, a fall of this magnitude. An estimated 23 tonnes of fragments survived the fiery passage through the atmosphere and reached the Earth.
Moldavite is a forest green, olive green or blue greenish vitreous silica projectile glass formed by a meteorite impact in southern Germany that occurred about 15 million years ago. It is a type of tektite and a gemstone. Material ejected from the impact crater includes moldavite, which was strewn across parts of Germany, the Czech Republic and Austria.
Libyan desert glass or Great Sand Sea glass is an impactite, made mostly of lechatelierite, found in areas in the eastern Sahara, in the deserts of eastern Libya and western Egypt. Fragments of desert glass can be found over areas of tens of square kilometers.
Darwin glass is a natural glass found south of Queenstown in West Coast, Tasmania. It takes its name from Mount Darwin in the West Coast Range, where it was first reported, and later gave its name to Darwin Crater, a probable impact crater, and the inferred source of the glass.
The Australasian strewnfield is the youngest and largest of the tektite strewnfields, with recent estimates suggesting it might cover 10%–30% of the Earth's surface. Research indicates that the impact forming the tektites occurred around 788,000 years ago, most likely in Southeast Asia.
The Carancas impact event refers to the fall of the Carancas chondritic meteorite on September 15, 2007, near the village of Carancas in Peru, close to the Bolivian border and Lake Titicaca. The impact created a small crater in the clay soil and scorched earth around its location. A local official, Marco Limache, said that "boiling water started coming out of the crater, and particles of rock and cinders were found nearby", as "fetid, noxious" gases spewed from the crater. Surface impact occurred above 3,800 metres (12,500 ft).
Total known weight (TKW), also total known mass, is a term used mainly by dealers and meteorite collectors to indicate the combined weight of all known pieces from a single named meteorite. The total known mass of a named meteorite is a fraction of the mass of the original meteoroid that entered Earth's atmosphere to produce the meteorite.
An explosion is a rapid expansion in volume of a given amount of matter associated with an extreme outward release of energy, usually with the generation of high temperatures and release of high-pressure gases. Explosions may also be generated by a slower expansion that would normally not be forceful, but is not allowed to expand, so that when whatever is containing the expansion is broken by the pressure that builds as the matter inside tries to expand, the matter expands forcefully. An example of this is a volcanic eruption created by the expansion of magma in a magma chamber as it rises to the surface. Supersonic explosions created by high explosives are known as detonations and travel through shock waves. Subsonic explosions are created by low explosives through a slower combustion process known as deflagration.
A meteor air burst is a type of air burst in which a meteoroid explodes after entering a planetary body's atmosphere. This fate leads them to be called fireballs or bolides, with the brightest air bursts known as superbolides. Such meteoroids were originally asteroids and comets of a few to several tens of meters in diameter. This separates them from the much smaller and far more common "shooting stars", that usually burn up quickly upon atmospheric entry.
Australites are tektites found in Australia. They are mostly dark or black, and have shapes including discs and bowls that are not seen in other tektites. NASA used the shape of "flanged button" australites in designing re-entry modules for the Apollo program in the 1960s.
The Weston meteorite is an H4 ordinary chondrite meteorite which fell to earth above the town of Weston, Connecticut on the morning of December 14, 1807.
The Sutter's Mill meteorite is a carbonaceous chondrite which entered the Earth's atmosphere and broke up at about 07:51 Pacific Time on April 22, 2012, with fragments landing in the United States. The name comes from Sutter's Mill, a California Gold Rush site, near which some pieces were recovered. Meteor astronomer Peter Jenniskens assigned Sutter's Mill (SM) numbers to each meteorite, with the documented find location preserving information about where a given meteorite was located in the impacting meteoroid. As of May 2014, 79 fragments had been publicly documented with a find location. The largest (SM53) weighs 205 grams (7.2 oz), and the second largest (SM50) weighs 42 grams (1.5 oz).
This is a glossary of terms used in meteoritics, the science of meteorites.
On 4 May 2014 around 4:17pm (EDT) a daylight bolide occurred near Ontario, resulting in a meteor air burst. The meteoroid was estimated to be roughly 50–100 centimetres in diameter. The explosion was estimated to be equivalent to approximately 10–20 tons of TNT. The meteor was first seen in Peterborough and traveled on a southwest-to-northeast trajectory. A meteor of this size impacts Earth about twice a week.
2022 WJ1, formerly designated C8FF042, was a small, harmless ≈1-metre near-Earth asteroid or meteoroid that impacted Earth's atmosphere on 19 November 2022 at 08:27 UT in Southern Ontario, Canada, above the Golden Horseshoe region, southwest of Toronto. Meteorites were detected by weather radar during dark flight.
