Carancas impact event
Encyclopedia
The Carancas impact event refers to the fall of the Carancas chondritic
Chondrite
Chondrites are stony meteorites that have not been modified due to melting or differentiation of the parent body. They formed when various types of dust and small grains that were present in the early solar system accreted to form primitive asteroids...

 meteorite
Meteorite
A meteorite is a natural object originating in outer space that survives impact with the Earth's surface. Meteorites can be big or small. Most meteorites derive from small astronomical objects called meteoroids, but they are also sometimes produced by impacts of asteroids...

 on September 15, 2007, near the village of Carancas in Peru
Peru
Peru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....

, close to the Bolivia
Bolivia
Bolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...

n border and Lake Titicaca
Lake Titicaca
Lake Titicaca is a lake located on the border of Peru and Bolivia. It sits 3,811 m above sea level, making it the highest commercially navigable lake in the world...

. The impact created a crater 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.

After the impact, villagers who had approached the impact site grew sick from a then-unexplained illness, with a wide array of symptoms. Two days later, Peruvian scientists confirmed that there had indeed been a meteorite strike, quieting widespread speculation that it may have been a geophysical rather than a celestial event. At that point, no further information on the cause of the mystery illness was known. The ground water in the local area is known to contain arsenic
Arsenic
Arsenic is a chemical element with the symbol As, atomic number 33 and relative atomic mass 74.92. Arsenic occurs in many minerals, usually in conjunction with sulfur and metals, and also as a pure elemental crystal. It was first documented by Albertus Magnus in 1250.Arsenic is a metalloid...

 compounds, and the illness is now believed to have been caused by arsenic poisoning
Arsenic poisoning
Arsenic poisoning is a medical condition caused by increased levels of the element arsenic in the body. Arsenic interferes with cellular longevity by allosteric inhibition of an essential metabolic enzyme...

 incurred when residents of the area inhaled the vapor
Vapor
A vapor or vapour is a substance in the gas phase at a temperature lower than its critical point....

 of the boiling arsenic-contaminated water.

The impact event

At 11:45 local time (16:45 GMT) on September 15, 2007, a chondritic
Chondrite
Chondrites are stony meteorites that have not been modified due to melting or differentiation of the parent body. They formed when various types of dust and small grains that were present in the early solar system accreted to form primitive asteroids...

 meteorite
Meteorite
A meteorite is a natural object originating in outer space that survives impact with the Earth's surface. Meteorites can be big or small. Most meteorites derive from small astronomical objects called meteoroids, but they are also sometimes produced by impacts of asteroids...

 crashed near the village of Carancas in the Puno Region
Puno Region
Puno is a region in southeastern Peru. It is bordered by Bolivia on the east, the Madre de Dios Region on the north, the Cusco and Arequipa regions on the west, the Moquegua Region on the southwest, and the Tacna Region on the south...

, Peru
Peru
Peru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....

, near the Bolivia
Bolivia
Bolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...

n border and Lake Titicaca
Lake Titicaca
Lake Titicaca is a lake located on the border of Peru and Bolivia. It sits 3,811 m above sea level, making it the highest commercially navigable lake in the world...

 (see map box on right). The impact created a crater larger than 4.5 m (15 ft) deep, 13 m (43 ft) wide, with visibly scorched earth around the impact site. 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. The crater size was given as 13.80 by 13.30 meters (45.28 by 43.64 feet), with its greatest dimensions in an east-west direction. The fireball had been observed by the locals as strongly luminous with a smoky tail, and seen from just 1000 meters (3280.84 ft) above the ground. The object moved in a direction toward N030E. The strong explosion at impact shattered the windows of the local health center 1 kilometre (0.621372736649807 mi) away. A smoke column was formed at the site that lasted several minutes, and boiling water was seen in the crater.

Soon after the impact, over 600 villagers who had visited the site began to fall ill from unexplained causes, including symptoms of dermal injuries, nausea
Nausea
Nausea , is a sensation of unease and discomfort in the upper stomach with an involuntary urge to vomit. It often, but not always, precedes vomiting...

, headaches, diarrhea
Diarrhea
Diarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...

 and vomiting
Vomiting
Vomiting is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose...

. On September 20, Peruvian scientists confirmed that there had been a meteorite strike, but no further information on the cause of the illnesses was known. Impact crater
Impact crater
In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...

 specialists have called the impact unusual, and have stated that the meteorite was at least 3 m (10 ft) in diameter before breaking up. The ground water in the area is known to contain arsenic
Arsenic
Arsenic is a chemical element with the symbol As, atomic number 33 and relative atomic mass 74.92. Arsenic occurs in many minerals, usually in conjunction with sulfur and metals, and also as a pure elemental crystal. It was first documented by Albertus Magnus in 1250.Arsenic is a metalloid...

 compounds, and the illness was believed to have been caused by arsenic poisoning
Arsenic poisoning
Arsenic poisoning is a medical condition caused by increased levels of the element arsenic in the body. Arsenic interferes with cellular longevity by allosteric inhibition of an essential metabolic enzyme...

 incurred when residents of the area inhaled the vapor
Vapor
A vapor or vapour is a substance in the gas phase at a temperature lower than its critical point....

 of the boiling arsenic-contaminated water.
However, further investigations have led to the conclusion that the arsenic content in the groundwater did not differ from that of the local drinking supply, and that the illness reported was likely caused by the vaporization of troilite, a sulfur-bearing compound present within the meteorite in large amounts, and which would have melted at relatively low temperatures and high pressures created by such an impact.

According to cosmochemist
Cosmochemistry
Cosmochemistry or chemical cosmology is the study of the chemical composition of matter in the universe and the processes that led to those compositions. This is done primarily through the study of the chemical composition of meteorites and other physical samples...

 Larry Grossman of the University of Chicago
University of Chicago
The University of Chicago is a private research university in Chicago, Illinois, USA. It was founded by the American Baptist Education Society with a donation from oil magnate and philanthropist John D. Rockefeller and incorporated in 1890...

, the aerial lights and explosions reported were consistent with extraterrestrial
Outer space
Outer space is the void that exists between celestial bodies, including the Earth. It is not completely empty, but consists of a hard vacuum containing a low density of particles: predominantly a plasma of hydrogen and helium, as well as electromagnetic radiation, magnetic fields, and neutrinos....

 material.

The loud noise and explosive impact originally led Peruvians to think that the neighboring nation of Chile
Chile
Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...

 had launched an attack.

Nature of the object

A report from three geologists at Peru’s Geophysics Institute was released on Thursday, September 20. Astrophysicist Jose Ishitsuka confirmed that there had been a meteorite strike.

On September 20, the X-Ray Laboratory at the Faculty of Geological Sciences, Mayor de San Andres University, La Paz, Bolivia, published a report of their analysis of a small sample of material recovered from the impact site. They detected iron, nickel
Nickel
Nickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...

, cobalt
Cobalt
Cobalt is a chemical element with symbol Co and atomic number 27. It is found naturally only in chemically combined form. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal....

, and traces of iridium
Iridium
Iridium is the chemical element with atomic number 77, and is represented by the symbol Ir. A very hard, brittle, silvery-white transition metal of the platinum family, iridium is the second-densest element and is the most corrosion-resistant metal, even at temperatures as high as 2000 °C...

 — elements characteristic of the elemental composition of meteorites. The quantitative proportions of silicon
Silicon
Silicon is a chemical element with the symbol Si and atomic number 14. A tetravalent metalloid, it is less reactive than its chemical analog carbon, the nonmetal directly above it in the periodic table, but more reactive than germanium, the metalloid directly below it in the table...

, aluminum, potassium
Potassium
Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...

, calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...

, magnesium
Magnesium
Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...

, and phosphorus
Phosphorus
Phosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus as a mineral is almost always present in its maximally oxidized state, as inorganic phosphate rocks...

 are incompatible with rocks that are normally found at the surface of the Earth.

INGEMMET (Instituto Geológico Minero y Metalúrgico) of Peru released internally on September 21 a report on the Carancas meteorite fall. The release of the document to the public was delayed for one week. The researchers found that the fragments from the crater zone had a chondritic texture and the following mineral composition: pyroxene
Pyroxene
The pyroxenes are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. They share a common structure consisting of single chains of silica tetrahedra and they crystallize in the monoclinic and orthorhombic systems...

 (1) 40%, olivine
Olivine
The mineral olivine is a magnesium iron silicate with the formula 2SiO4. It is a common mineral in the Earth's subsurface but weathers quickly on the surface....

 20%, feldspar
Feldspar
Feldspars are a group of rock-forming tectosilicate minerals which make up as much as 60% of the Earth's crust....

 10%, pyroxene
Pyroxene
The pyroxenes are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. They share a common structure consisting of single chains of silica tetrahedra and they crystallize in the monoclinic and orthorhombic systems...

 (2) 10%; kamacite
Kamacite
Kamacite is a mineral. It is an alloy of iron and nickel, usually in the proportions of 90:10 to 95:5 although impurities such as cobalt or carbon may be present. On the surface of Earth, it occurs naturally only in meteorites. It has a metallic luster, is gray and has no clear cleavage although...

 15%, troilite
Troilite
Troilite is a rare iron sulfide mineral with the simple formula of FeS. It is the iron rich endmember of the pyrrhotite group. Pyrrhotite has the formula FeS which is iron deficient...

 5%, and traces of chromite
Chromite
Chromite is an iron chromium oxide: FeCr2O4. It is an oxide mineral belonging to the spinel group. Magnesium can substitute for iron in variable amounts as it forms a solid solution with magnesiochromite ; substitution of aluminium occurs leading to hercynite .-Occurrence:Chromite is found in...

 and native copper
Native copper
Copper, as native copper, is one of the few metallic elements to occur in uncombined form as a natural mineral, although most commonly occurs in oxidized states and mixed with other elements...

. Kamacite
Kamacite
Kamacite is a mineral. It is an alloy of iron and nickel, usually in the proportions of 90:10 to 95:5 although impurities such as cobalt or carbon may be present. On the surface of Earth, it occurs naturally only in meteorites. It has a metallic luster, is gray and has no clear cleavage although...

 occurs naturally only in meteorites.

The official classification of the Carancas meteorite, accepted by the Meteoritical Society
Meteoritical Society
The Meteoritical Society is a non-profit scholarly organization founded in 1933 to promote research and education in planetary science with emphasis on studies of meteorites and other extraterrestrial materials that further our understanding of the origin and history of the solar system.The...

 was done by a team of scientists working at the University of Arizona
University of Arizona
The University of Arizona is a land-grant and space-grant public institution of higher education and research located in Tucson, Arizona, United States. The University of Arizona was the first university in the state of Arizona, founded in 1885...

. The meteorite is an ordinary chondrite
Ordinary chondrite
The Ordinary chondrites are a class of stony chondritic meteorites. They are by far the most numerous group and comprise about 87% of all finds...

, an H chondrite
H chondrite
The H type ordinary chondrites are the most common type of meteorite, accounting for approximately 40% of all those catalogued, 46% of the ordinary chondrites, and 44% of the chondrites....

 breccia
Breccia
Breccia is a rock composed of broken fragments of minerals or rock cemented together by a fine-grained matrix, that can be either similar to or different from the composition of the fragments....

, containing clasts of petrologic types 4 to 5. The formal classification is H4-5. The meteoroid had experienced a considerable amount of shock
Shock (mechanics)
A mechanical or physical shock is a sudden acceleration or deceleration caused, for example, by impact, drop, kick, earthquake, or explosion. Shock is a transient physical excitation....

 before its ultimate encounter with Earth.
Further results are expected, and material is also going to be studied by NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

, British, and Japanese researchers according to media reports.

Illness complaints

Afterwards, local townspeople went to see what happened, and 100 to 200 people who got near to the meteorite crater soon reported feeling sick. First responding police officers arriving to investigate the scene also fell ill. After the initial event of September 15, the number of people falling ill increased, requiring physicians to establish auxiliary medical tents for the Carancas health center. Patients were treated for dermal injuries, nausea, headaches, diarrhea and vomiting. The death of nearby livestock was also reported. Locals made the decision to stop drinking from nearby water sources for fear of contamination and authorities considered declaring a state of emergency. Four days after the meteorite impact and the unexplained illness, most villagers reported having recovered.

Reported details about the event, such as water boiling in the muddy crater for ten minutes from the heat of the impact, presented a problem for experts. Because the impact site is at a high altitude of more than 3800 m (12,467 ft), the meteoroid may not have been slowed down as much as it ordinarily would have been by passage through the Earth’s denser lower atmosphere, and kinetic energy at impact may have been unusually high for a terrestrial impact of an object of this size and mass. Most larger meteorites are cold in their bulk mass when they land on Earth, since their heated outer layers ablate
Ablation
Ablation is removal of material from the surface of an object by vaporization, chipping, or other erosive processes. This occurs in spaceflight during ascent and atmospheric reentry, glaciology, medicine, and passive fire protection.-Spaceflight:...

 from the objects before impacting. It was later confirmed that the meteorite had high degrees of iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...

 and possessed magnetic properties common to similar metallic objects, which contributed to its capacity to retain heat during atmospheric entry
Atmospheric reentry
Atmospheric entry is the movement of human-made or natural objects as they enter the atmosphere of a celestial body from outer space—in the case of Earth from an altitude above the Kármán Line,...

.

Government response

In contrast with other international media reports, Peruvian health officials downplayed the incident. Jorge López Tejada, the Regional Health Director for Puno, Peru, denied any serious medical situation existed. However, a health brigade arrived with personnel and medication to the site on September 18, reporting that the odors rising from the crater were causing medical issues. Earlier, Tejada had stated that the officers were dizzy, nauseous and some were vomiting.

On September 19, Andina, Peru’s official government news agency, reported that the sick villagers appeared to be recovering somewhat. "They are recovering, there aren't any critical cases. A total of 200 people with different symptoms have been seen," stated López Tejada. Government officials also specifically asked people to avoid the "glowing object that fell from the sky."

Suspected etiology

Scientists initially ruled out radiation
Radiation
In physics, radiation is a process in which energetic particles or energetic waves travel through a medium or space. There are two distinct types of radiation; ionizing and non-ionizing...

 as the cause of the illness. Renan Ramirez of the Peruvian Nuclear Energy Institute stated that the medical conditions could have been caused by sulfur
Sulfur
Sulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...

, arsenic
Arsenic
Arsenic is a chemical element with the symbol As, atomic number 33 and relative atomic mass 74.92. Arsenic occurs in many minerals, usually in conjunction with sulfur and metals, and also as a pure elemental crystal. It was first documented by Albertus Magnus in 1250.Arsenic is a metalloid...

 or other toxins that may have melted in the extreme heat produced by the meteorite strike. Some unnamed Peruvian sources stated soon after the event occurred that it was indeed a meteorite. Later on September 18, a Peruvian vulcanologist stated that the impact was caused by a chondrite
Chondrite
Chondrites are stony meteorites that have not been modified due to melting or differentiation of the parent body. They formed when various types of dust and small grains that were present in the early solar system accreted to form primitive asteroids...

 meteorite arrival.

Some reports indicated initial suspicions that the illnesses may have been psychosomatic in nature. Don Yeomans, head of the Near Earth Object Program at NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

’s Jet Propulsion Laboratory
Jet Propulsion Laboratory
Jet Propulsion Laboratory is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. The facility is headquartered in the city of Pasadena on the border of La Cañada Flintridge and Pasadena...

 in Pasadena, California
Pasadena, California
Pasadena is a city in Los Angeles County, California, United States. Although famous for hosting the annual Rose Bowl football game and Tournament of Roses Parade, Pasadena is the home to many scientific and cultural institutions, including the California Institute of Technology , the Jet...

, said, “Statistically, it’s far more likely to have come from below than from above. The noxious fumes that have supposedly sickened curious locals who went to examine the crater would seem to indicate hydrothermal activity, such as a local gas explosion, because meteorites don't give off odors.”

By September 21, it was believed that the illness was caused by arsenic poisoning
Arsenic poisoning
Arsenic poisoning is a medical condition caused by increased levels of the element arsenic in the body. Arsenic interferes with cellular longevity by allosteric inhibition of an essential metabolic enzyme...

. Luisa Macedo of Peru’s Mining, Metallurgy, and Geology Institute said gases were created when the meteorite’s hot surface reacted with an underground water supply tainted with arsenic. Natural arsenic deposits in ground water are not uncommon in southern Peru. José Ishitsuka of the Peruvian Geophysics Institute said, “If the meteorite arrives incandescent and at a high temperature because of friction in the atmosphere, hitting water can create a column of steam.” Meteorites, however, often impact the earth at low temperatures, making this an unusual event.

External links

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