"of resources. He writes that Although, of course, the base could yield a great discovery, its scientific value is likely to be small while its price is extremely high. Worse, moon-base nonsense may for decades divert NASA resources from the agency's legitimate missions, draining funding from real needs in order to construct human history's silliest white elephant. According to Easterbrook, the billions of dollars that a lunar colony might cost should instead be devoted to exploring the solar system with space probes; space observatories; and protecting the Earth from near-Earth asteroids. Buzz Aldrin, the second of twelve men to have"
"time, the DFN expanded into an automated digital fireball observatory, which is now expanding further to new regions of Australia and overseas. So far, four meteorites have been recovered with a high-accuracy trajectory and orbit defined. Meteorites are metallic or stony objects that fall to the Earth's surface from space. Scientists believe that most meteorites originate from asteroids within the asteroid belt of our solar system, but there is an increasing amount of evidence to suggest some may come from comets. Some meteorites also come from larger planetary bodies, such as the moon and Mars. Meteorites typically preserve their histories"
"by humans. About 5% of meteorites that have been seen to fall are iron meteorites composed of iron-nickel alloys, such as kamacite and/or taenite. Most iron meteorites are thought to come from the cores of planetesimals that were once molten. As with the Earth, the denser metal separated from silicate material and sank toward the center of the planetesimal, forming its core. After the planetesimal solidified, it broke up in a collision with another planetesimal. Due to the low abundance of iron meteorites in collection areas such as Antarctica, where most of the meteoric material that has fallen can be"
"their elemental, isotopic and textural characteristics. Whereas most meteorites likely originate from asteroids, the contrasting makeup of micrometeorites suggests that most originate from comets. Fewer than 1% of MMs are achondritic and are similar to HED meteorites, which are thought to be from the asteroid, 4 Vesta. Most MMs are compositionally similar to carbonaceous chondrites, whereas approximately 3% of meteorites are of this type. The dominance of carbonaceous chondrite-like MMs and their low abundance in meteorite collections suggests that most MMs derive from sources different than those for most meteorites. Since most meteorites probably derive from asteroids, an alternative source"
"traditional sense, to Earth. It mainly comes from iron-nickel meteorites that formed millions of years ago but were preserved from chemical attack by the vacuum of space, and fell to the earth a relatively short time ago. Metallic meteorites are composed primarily of the iron-nickel alloys: taenite (high nickel content) and kamacite (low nickel content). However, there are a few areas on earth where truly native iron can be found. Native nickel has been described as serpentinite due to hydrothermal alteration of ultramafic rocks in New Caledonia and elsewhere. Metallic cobalt has been reported in the Canadian Lorraine Mine, Cobalt-Gowganda"
"from collisions can form meteoroids that enter the Earth's atmosphere. Of the 50,000 meteorites found on Earth to date, 99.8 percent are believed to have originated in the asteroid belt. In 1918, the Japanese astronomer Kiyotsugu Hirayama noticed that the orbits of some of the asteroids had similar parameters, forming families or groups. Approximately one-third of the asteroids in the asteroid belt are members of an asteroid family. These share similar orbital elements, such as semi-major axis, eccentricity, and orbital inclination as well as similar spectral features, all of which indicate a common origin in the breakup of a larger"
"grains of diamond about 2 nanometers in diameter (nanodiamonds). Trapped in them were noble gases whose isotopic signature indicated they came from outside the Solar System. Analyses of more meteorites found nanodiamonds from many different stars. The record of their origins was preserved despite a long and violent history that started when they were ejected from a star into the interstellar medium, went through the formation of the Solar System, were incorporated into a planetary body that was later broken up into meteorites, and finally crashed on the Earth's surface. In meteorites, nanodiamonds make up about 3 percent of the"
"found on Earth thought to be from Mars were indeed from Mars. The term does not refer to meteorites found on Mars, such as Heat Shield Rock. On January 3, 2013, NASA reported that a meteorite, named ""NWA 7034"" (nicknamed ""Black Beauty""), found in 2011, in the Sahara desert, was determined to be from Mars and found to contain ten times the water of other Mars meteorites found on Earth. The meteorite contains components as old as 4.42 ± 0.07 Ga (billion years), and was heated during the Amazonian geologic period on Mars. By the early 1980s, it was obvious"
"pyrimidine, found in meteorites. Pyrimidine, like polycyclic aromatic hydrocarbons (PAHs), the most carbon-rich chemical found in the Universe, may have been formed in red giants or in interstellar dust and gas clouds, according to the scientists. In January 2018, researchers found that 4.5 billion-year-old meteorites found on Earth contained liquid water along with prebiotic complex organic substances that may be ingredients for life. Most meteorite falls are recovered on the basis of eyewitness accounts of the fireball or the impact of the object on the ground, or both. Therefore, despite the fact that meteorites fall with virtually equal probability everywhere"
"Willamette Meteorite The Willamette Meteorite, officially named Willamette, is an iron-nickel meteorite found in the U.S. state of Oregon. It is the largest meteorite found in North America and the sixth largest in the world. There was no impact crater at the discovery site; researchers believe the meteorite landed in what is now Canada or Montana, and was transported as a glacial erratic to the Willamette Valley during the Missoula Floods at the end of the last Ice Age (~13,000 years ago). It was long held sacred by indigenous peoples of the Willamette Valley, including the federally recognized Confederated Tribes"
"now more than 30,000 meteorite finds in the world's collections started with the discovery by Harvey H. Nininger that meteorites are much more common on the surface of the Earth than was previously thought. Nininger's strategy was to search for meteorites in the Great Plains of the United States, where the land was largely cultivated and the soil contained few rocks. Between the late 1920s and the 1950s, he traveled across the region, educating local people about what meteorites looked like and what to do if they thought they had found one, for example, in the course of clearing a"
"also by shedding glowing material in its wake. Although a meteor may seem to be a few thousand feet from the Earth, meteors typically occur in the mesosphere at altitudes from . The root word ""meteor"" comes from the Greek ""meteōros"", meaning ""high in the air"". Millions of meteors occur in Earth's atmosphere daily. Most meteoroids that cause meteors are about the size of a grain of sand, i.e. they are usually millimeter-sized or smaller. Meteoroid sizes can be calculated from their mass and density which, in turn, can be estimated from the observed meteor trajectory in the upper atmosphere."
"sheet tends to concentrate the meteorites at blocking locations such as mountain ranges, with wind erosion bringing them to the surface after centuries beneath accumulated snowfall. Compared with meteorites collected in more temperate regions on Earth, the Antarctic meteorites are well-preserved. This large collection of meteorites allows a better understanding of the abundance of meteorite types in the solar system and how meteorites relate to asteroids and comets. New types of meteorites and rare meteorites have been found. Among these are pieces blasted off the Moon, and probably Mars, by impacts. These specimens, particularly ALH84001 discovered by ANSMET, are at"
"primordial origin. Meteorites are believed to represent the major composition of material from which the Earth was formed. Some meteorites, such as carbonaceous chondrites, contain carbonaceous material. If a large amount of this material is still within the Earth, it could have been leaking upward for billions of years. The thermodynamic conditions within the mantle would allow many hydrocarbon molecules to be at equilibrium under high pressure and high temperature. Although molecules in these conditions may disassociate, resulting fragments would be reformed due to the pressure. An average equilibrium of various molecules would exist depending upon conditions and the carbon-hydrogen"
"that recovered Pribram, led to the discovery and orbit calculations for the ""Neuschwanstein"" meteorite in 2002. NASA has an automated system that detects meteors and calculates the orbit, magnitude, ground track, and other parameters over the southeast USA, which often detects a number of events each night. Until the twentieth century, only a few hundred meteorite finds had ever been discovered. More than 80% of these were iron and stony-iron meteorites, which are easily distinguished from local rocks. To this day, few stony meteorites are reported each year that can be considered to be ""accidental"" finds. The reason there are"
"contamination"". This caused additional interest in this meteorite, so in 2006, NASA managed to obtain an additional and larger sample from the London Natural History Museum. On this second sample, a large dendritic carbon content was observed. When the results and evidence were published in 2006, some independent researchers claimed that the carbon deposits are of biologic origin. It was remarked that since carbon is the fourth most abundant element in the Universe, finding it in curious patterns is not indicative or suggestive of biological origin. The Shergotty meteorite, a 4 kg Martian meteorite, fell on Earth on Shergotty, India"
"Greek ""tektos"", molten) are not themselves meteorites, but are rather natural glass objects up to a few centimeters in size that were formed—according to most scientists—by the impacts of large meteorites on Earth's surface. A few researchers have favored tektites originating from the Moon as volcanic ejecta, but this theory has lost much of its support over the last few decades. In March 2015, NASA scientists reported that, for the first time, complex organic compounds found in DNA and RNA, including uracil, cytosine and thymine, have been formed in the laboratory under outer space conditions, using starting chemicals, such as"
"Chondrite Chondrites are stony (non-metallic) meteorites that have not been modified due to melting or differentiation of the parent body. They are formed when various types of dust and small grains that were present in the early solar system accreted to form primitive asteroids. They are the most common type of meteorite that falls to Earth with estimates for the proportion of the total fall that they represent varying between 85.7% and 86.2%. Their study provides important clues for understanding the origin and age of the Solar System, the synthesis of organic compounds, the origin of life and the presence"
"many of the less common meteorites mesosiderites and E chondrites. E chondrites are chondrites which are made primarily of enstatite and only account for 2% of meteorites that fall onto the Earth. E chondrites have an entirely different source rock than that of the ordinary chondrites. In analysis of kamacite in E chondrites it was found that they contain generally less nickel then average. Since kamacite is only formed in space and is only found on Earth in meteorites, it has very low abundance on Earth. Its abundance outside our solar system is difficult to determine. Iron, the main component"
"of most planets. Some meteorites contain microscopic diamonds that were formed when the solar system was still a protoplanetary disk. Microscopic diamonds may also be formed by the intense pressure and high temperature at the sites of meteorite impacts. In 2014 NASA announced a greatly upgraded database for tracking polycyclic aromatic hydrocarbons (PAHs) in the universe. More than 20% of the carbon in the universe may be associated with PAHs, complex compounds of carbon and hydrogen without oxygen. These compounds figure in the PAH world hypothesis where they are hypothesized to have a role in abiogenesis and formation of life."
"of the rest of the Solar System (in particular, the Sun), and which differ from each other, indicating sources in a number of different explosive supernova events. Meteorites also may contain interstellar dust grains, which have collected from non-gaseous elements in the interstellar medium, as one type of composite cosmic dust (""stardust"") Recent findings by NASA, based on studies of meteorites found on Earth, suggests DNA and RNA components (adenine, guanine and related organic molecules), building blocks for life as we know it, may be formed extraterrestrially in outer space. On 30 July 2015, scientists reported that upon the first"
"Meteorite 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 object enters the atmosphere, various factors such as friction, pressure, and chemical interactions with the atmospheric gases cause it to heat up and radiate that energy. It then becomes a meteor and forms a fireball, also known as a shooting star or falling star; astronomers call the brightest examples ""bolides"". Meteorites vary greatly in size. For geologists, a"
"could have had an extraterrestrial origin. Chondrite Chondrites are stony (non-metallic) meteorites that have not been modified due to melting or differentiation of the parent body. They are formed when various types of dust and small grains that were present in the early solar system accreted to form primitive asteroids. They are the most common type of meteorite that falls to Earth with estimates for the proportion of the total fall that they represent varying between 85.7% and 86.2%. Their study provides important clues for understanding the origin and age of the Solar System, the synthesis of organic compounds, the"
"scientists recognized that they had also collected a lunar meteorite, Yamato 791197, during the 1979 field season in Antarctica. , about 306 lunar meteorites have been discovered, perhaps representing more than 30 separate meteorite falls (i.e., many of the stones are ""paired"" fragments of the same meteoroid). The total mass is more than . All lunar meteorites have been found in deserts; most have been found in Antarctica, northern Africa, and the Sultanate of Oman. None have yet been found in North America, South America, or Europe. Lunar origin is established by comparing the mineralogy, the chemical composition, and the"
"cases, the largest meteorites in a shower are found farthest down-range in the strewn field. Most meteorites are stony meteorites, classed as chondrites and achondrites. Only about 6% of meteorites are iron meteorites or a blend of rock and metal, the stony-iron meteorites. Modern classification of meteorites is complex. The review paper of Krot et al. (2007) summarizes modern meteorite taxonomy. About 86% of the meteorites are chondrites, which are named for the small, round particles they contain. These particles, or chondrules, are composed mostly of silicate minerals that appear to have been melted while they were free-floating objects in"
"elements in Earth's crust, is found in the Willamette Meteorite at a concentration of 4.7 ppm, thousands of times more concentrated than in the crust. The lack of an impact crater at the discovery site was only explained after the 1920s, with the new understanding about the Missoula Floods, one of the largest floods documented, caused by the collapse of an ice barrier during the last deglaciation. The meteorite presumably landed on an ice cap in what is now Montana or western Canada, and was dragged by the glacier ice to the vicinity of an ice barrier that formed across"
"into groups based on the chondrules present. There are three major types: enstatite chondrites, carbonaceous chondrites and ordinary chondrites. Ordinary chondrites are the most abundant type of meteorite found on Earth making up 85% of all meteorites recorded. Ordinary chondrites are thought to have all originated from three different sources thus they come in three types LL, L, and H; LL stands for Low iron, Low metal, L stands for Low iron abundance, and H is High iron content. All ordinary chondrites contain kamacite in decreasing abundance as you move from H to LL chondrites. Kamacite is also found in"
"and lunar samples. At the same time, he began theoretical explorations into the origin of meteorites. His studies concentrated on collisions between objects in the asteroid belt together with resonances between their motions and those of planets. He computed how these events could move material into Earth-crossing orbits to become meteorites or larger Earth-impacting bodies responsible for the devastating impacts that caused mass extinctions of the majority of living species, including the dinosaurs. Later, he, along with scientists elsewhere, proposed that a certain unusual class of meteorites was not asteroidal in origin but instead came from the planet Mars. This"
"of the orange spectrographic bands in the spectrum of the upper atmosphere. Meteoric iron Meteoric iron, sometimes meteoritic iron, is a native metal found in meteorites and made from the elements iron and nickel mainly in the form of the mineral phases kamacite and taenite. Meteoric iron makes up the bulk of iron meteorites but is also found in other meteorites. Apart from minor amounts of telluric iron, meteoric iron is the only naturally occurring native metal of the element iron on the Earth's surface. The bulk of meteoric iron consists of taenite and kamacite. Taenite is a face centered"
"of kamacite, is the sixth most abundant element in the universe and the most abundant of those elements generally considered metallic. Taenite, and tochilinite are minerals that are commonly associated with kamacite. Kamacite has been found and studied in Meteor Crater, Arizona. Meteor Crater was the first confirmed meteor impact site on the planet, and was not universally recognized as such till the 1950s. In the 1960s United States Geological Survey discovered kamacite in specimens gathered from around the site tying the mineral to meteorites. Kamacite primarily forms on meteorites but has been found on extraterrestrial bodies such as Mars."
"rocks known, with most of their iron taking the form of metal or sulfide rather than as an oxide. This suggests that they were formed in an area that lacked oxygen, probably within the orbit of Mercury. Ordinary chondrites are by far the most common type of meteorite to fall to Earth: about 80% of all meteorites and over 90% of chondrites are ordinary chondrites. They contain abundant chondrules, sparse matrix (10–15% of the rock), few refractory inclusions, and variable amounts of Fe-Ni metal and troilite (FeS). Their chondrules are generally in the range of 0.5 to 1 mm in"
"by X-rays from the Sun scattering off the upper Martian atmosphere; the second comes from interactions between ions that result in an exchange of charges. The emission from the latter source has been observed out to eight times the radius of Mars by the XMM-Newton orbiting observatory. In 1983, the analysis of the shergottite, nakhlite, and chassignite (SNC) group of meteorites showed that they may have originated on Mars. The Allan Hills 84001 meteorite, discovered in Antarctica in 1984, is believed to have originated on Mars but it has an entirely different composition than the SNC group. In 1996, it"
"soil. Stony meteorites —which make up the large majority of meteorites that fall— may not have a high enough nickel iron content to set off a metal detector. Large and very sensitive metal detectors may be used as well as ground-penetrating radar, lidar, and even landmine detectors. Although meteorites fall uniformly across the globe they do not typically remain on the surface in areas with a large amount of yearly rainfall. If a newly fallen meteorite is not recovered within a few months it is likely to be buried with alluvium or covered by plant growth. Some arctic and desert"