A meteorite is a rock that originated in outer space and has fallen to 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.
Meteor Crater or Barringer Crater is an impact crater about 37 mi (60 km) east of Flagstaff and 18 mi (29 km) west of Winslow in the desert of northern Arizona, United States. The site had several earlier names, and fragments of the meteorite are officially called the Canyon Diablo Meteorite, after the adjacent Canyon Diablo.
An impact event is a collision between astronomical objects causing measurable effects. Impact events have been found to regularly occur in planetary systems, though the most frequent involve asteroids, comets or meteoroids and have minimal effect. When large objects impact terrestrial planets such as the Earth, there can be significant physical and biospheric consequences, as the impacting body is usually traveling at several kilometres a second, though atmospheres mitigate many surface impacts through atmospheric entry. Impact craters and structures are dominant landforms on many of the Solar System's solid objects and present the strongest empirical evidence for their frequency and scale.
Boxhole is a young impact crater located approximately 180 km north-east of Alice Springs in the Northern Territory, Australia. It is 170 metres in diameter and its age is estimated to be 5,400 ± 1,500 years based on the cosmogenic 14C terrestrial age of the meteorite, placing it in the Holocene. The crater is exposed to the surface.
Dalgaranga crater is a small meteorite impact crater located on Dalgaranga pastoral station 75 km (47 mi) northwest of Mount Magnet in Western Australia. It is only 24 m (79 ft) in diameter and 3 m (9.8 ft) deep, making it Australia's smallest impact crater. Though discovered in 1921, it was not reported in the scientific literature until 1938. The bedrock at the site is weathered Archaean granite of the Yilgarn Craton. The discovery of fragments of mesosiderite stony-iron meteorite around the crater confirms an impact origin, making this crater unique as the only one known to have been produced by a mesosiderite projectile.
Gosses Bluff is thought to be the eroded remnant of an impact crater. Known as Tnorala to the Western Arrernte people of the surrounding region, it is located in the southern Northern Territory, near the centre of Australia, about 175 km (109 mi) west of Alice Springs and about 212 km (132 mi) to the northeast of Uluru. It was named by Ernest Giles in 1872 after Australian explorer William Gosse's brother Henry, who was a member of William's expedition.
Liverpool is a meteorite impact crater situated in Arnhem Land within the Northern Territory, Australia. It was named after the nearby Liverpool River. Liverpool is remote and difficult to access. The crater has a raised, near-circular rim averaging about 1.6 km in diameter. It was first noticed by geologists during reconnaissance geological mapping in the 1960s, and although an impact origin was considered possible, this was not confirmed until a more detailed study was undertaken in 1970.
Maple Creek is a subterranean meteorite crater in Saskatchewan, Canada. It is 6 km (3.7 mi) in diameter and the age is estimated to be less than 75 million years. The crater is buried beneath younger sediment and cannot be seen at the surface.
Talemzane or madena is an impact crater in Algeria, 40 km south-east of Hassi Delaa.
Veevers crater is an impact crater located on a flat desert plain between the Great Sandy and Gibson Deserts in the centre of the state of Western Australia.
Viewfield is an impact crater in Saskatchewan, Canada. It is 2.5 kilometres (1.6 mi) in diameter and the age is estimated to be 190 ± 20 million years. The crater is not exposed at the surface.
Woodleigh is a large meteorite impact structure (astrobleme) in Western Australia, centred on Woodleigh Station east of Shark Bay, Gascoyne region. A team of four scientists at the Geological Survey of Western Australia and the Australian National University, led by Arthur J. Mory, announced the discovery in the 15 April 2000 issue of Earth and Planetary Science Letters.
The Yarrabubba impact structure is the eroded remnant of an impact crater, situated in the northern Yilgarn Craton near Yarrabubba Station between the towns of Sandstone and Meekatharra, Mid West Western Australia. With an age of 2.229 billion years, it is the oldest known impact structure on Earth.
Halls Creek is a town situated in the east Kimberley region of Western Australia. It is located between the towns of Fitzroy Crossing and Turkey Creek (Warmun) on the Great Northern Highway. It is the only sizable town for 600 km on the Highway.
Henbury Meteorites Conservation Reserve is a protected area in the Northern Territory of Australia located in the locality of Ghan.
The Hickman crater is a recently discovered meteorite impact crater, 16 kilometres northeast of the Hope Downs 4 Mine and 35 kilometres north of Newman in the Ophthalmia Range, Western Australia. It was discovered by Arthur Hickman, a government geologist with the Geological Survey of Western Australia, in July 2007. The discovery was made by chance while browsing Google Earth. A 2012 government scientific drilling project in the centre of the crater confirmed in 2017 the impact of an iron-nickel meteorite.
Ramgarh crater, also known as Ramgarh structure, Ramgarh Dome and Ramgarh astrobleme, is a meteor impact crater of 3.5 kilometres (2.2 mi) diameter in Kota plateau of Vindhya Range located adjacent to Ramgarh village in Mangrol tehsil of Baran district in Rajasthan state of India. When formally accepted as the third crater in India, its diameter size would be between the two already confirmed craters in India - Dhala in Madhya Pradesh with 14 km diameter and Lonar in Buldhana district of Maharashtra with 1.8 km diameter.
Mars may contain ores that would be very useful to potential colonists. The abundance of volcanic features together with widespread cratering are strong evidence for a variety of ores. While nothing may be found on Mars that would justify the high cost of transport to Earth, the more ores that future colonists can obtain from Mars, the easier it would be to build colonies there.
