Allan Hills 77005 (also known as Allan Hills A77005, ALHA77005, ALH77005 and ALH-77005
) is a
Martian meteorite
A Martian meteorite is a rock that formed on Mars, was ejected from the planet by an impact event, and traversed interplanetary space before landing on Earth as a meteorite. , 277 meteorites had been classified as Martian, less than half a percen ...
that was found in the
Allan Hills
The Allan Hills are a group of hills at the end of the Transantarctic Mountains System, located in Oates Land and Victoria Land regions of Antarctica.
They are mainly ice free and about long, lying just north-west of the Coombs Hills near th ...
of
Antarctica
Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest contine ...
in 1977 by a
Japanese National Institute of Polar Research mission team and
ANSMET
ANSMET (Antarctic Search for Meteorites) is a program funded by the Office of Polar Programs of the National Science Foundation that looks for meteorites in the Transantarctic Mountains. This geographical area serves as a collection point for mete ...
.
Like other members of the group of
SNCs (
shergottite
A Martian meteorite is a rock that formed on Mars, was ejected from the planet by an impact event, and traversed interplanetary space before landing on Earth as a meteorite. , 277 meteorites had been classified as Martian, less than half a percen ...
,
nakhlite
Nakhlites are a group of Martian meteorites, named after the first one, Nakhla meteorite.
Nakhlites are igneous rocks that are rich in augite and were formed from basaltic magma about 1.3 billion years ago. They contain augite and olivine crysta ...
,
chassignite
A Martian meteorite is a rock that formed on Mars, was ejected from the planet by an impact event, and traversed interplanetary space before landing on Earth as a meteorite. , 277 meteorites had been classified as Martian, less than half a percen ...
), ALH-77005 is thought to be from
Mars
Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury (planet), Mercury. In the English language, Mars is named for the Mars (mythology), Roman god of war. Mars is a terr ...
.
Description
On discovery, the
mass
Mass is an intrinsic property of a body. It was traditionally believed to be related to the quantity of matter in a physical body, until the discovery of the atom and particle physics. It was found that different atoms and different elementar ...
of ALH-77005 was . Initial geological examination determined that the meteorite was composed of ~55%
olivine
The mineral olivine () is a magnesium iron silicate with the chemical formula . It is a type of nesosilicate or orthosilicate. The primary component of the Earth's upper mantle, it is a common mineral in Earth's subsurface, but weathers quickl ...
, ~35%
pyroxene
The pyroxenes (commonly abbreviated to ''Px'') are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. Pyroxenes have the general formula , where X represents calcium (Ca), sodium (Na), iron (Fe II) ...
, ~8%
maskelynite
Maskelynite is a glassy material found in some meteorites and meteorite impact craters. Typical samples are similar in composition to plagioclase feldspar, and revert to that mineral when melted and recrystallized. It was named after British geolog ...
and ~2% opaques.
In March 2019, researchers reported the possibility of
biosignature
A biosignature (sometimes called chemical fossil or molecular fossil) is any substance – such as an element, isotope, or molecule – or phenomenon that provides scientific evidence of past or present life. Measurable attribute ...
s in this
Martian meteorite
A Martian meteorite is a rock that formed on Mars, was ejected from the planet by an impact event, and traversed interplanetary space before landing on Earth as a meteorite. , 277 meteorites had been classified as Martian, less than half a percen ...
based on its microtexture and morphology as detected with
optical microscopy
Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultraviole ...
and
FTIR-ATR microscopy, and on the detection of mineralized
organic compound
In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The ...
s,
suggesting that
microbial life
A microorganism, or microbe,, ''mikros'', "small") and ''organism'' from the el, ὀργανισμός, ''organismós'', "organism"). It is usually written as a single word but is sometimes hyphenated (''micro-organism''), especially in olde ...
could have existed on the planet Mars.
More broadly, and as a result of their studies, the researchers suggest
Solar System
The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar S ...
materials should be carefully studied to determine whether there may be signs of
microbial forms within other
space rocks as well.
See also
*
Allan Hills 84001
Allan Hills 84001 (ALH84001) is a fragment of a Martian meteorite that was found in the Allan Hills in Antarctica on December 27, 1984, by a team of American meteorite hunters from the ANSMET project. Like other members of the shergottite–nakhl ...
*
Glossary of meteoritics
This is a glossary of terms used in meteoritics, the science of meteorites.
#
* 2 Pallas – an asteroid from the asteroid belt and one of the likely parent bodies of the CR meteorites.
* 4 Vesta – second-largest asteroid in the asteroid b ...
*
History of Mars observation
The history of Mars observation is about the recorded history of observation of the planet Mars. Some of the early records of Mars' observation date back to the era of the ancient Egyptian astronomers in the 2nd millennium BCE. Chinese records a ...
*
Life on Mars
The possibility of life on Mars is a subject of interest in astrobiology due to the planet's proximity and similarities to Earth. To date, no proof of past or present life has been found on Mars. Cumulative evidence suggests that during the ...
*
List of Martian meteorites on Earth
*
List of meteorites on Mars
This is an alphabetical list of named rocks (and meteorites) found on Mars, by mission. This list is a sampling of rocks viewed, and is not an exhaustive listing. A more complete listing may be found on the various NASA mission web sites. This lis ...
*
Nakhla meteorite
Nakhla is a Martian meteorite which fell in Egypt in 1911. It was the first meteorite reported from Egypt, the first one to suggest signs of aqueous processes on Mars, and the prototype for Nakhlite type of meteorites.
History
The Nakhla met ...
*
Mars sample return mission
*
Panspermia
Panspermia () is the hypothesis, first proposed in the 5th century BCE by the Greek philosopher Anaxagoras, that life exists throughout the Universe, distributed by space dust, meteoroids, asteroids, comets, and planetoids, as well as by spacecraf ...
*
Shergotty meteorite
The Shergotty meteorite (Named after Sherghati) is the first example of the shergottite Martian meteorite family. It was a meteorite which fell to Earth at Sherghati, in the Gaya district, Bihar, India on 25 August 1865, and was retrieved by witne ...
*
Water on Mars
Almost all water on Mars today exists as ice, though it also exists in small quantities as vapor in the atmosphere. What was thought to be low-volume liquid brines in shallow Martian soil, also called recurrent slope lineae, may be grains of f ...
References
Further reading
*
External links
Meteoritical SocietyThe British and Irish Meteorite SocietyThe Natural History Museum's meteorite catalogue database
{{Portal bar, Astronomy, Biology, Solar System
Astrobiology
Extraterrestrial life
Martian meteorites
Meteorites found in Antarctica