Amirani is an active
volcano
A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.
On Earth, volcanoes are most oft ...
on
Jupiter's moon
The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...
Io, the inner-most of the
Galilean Moons
The Galilean moons (), or Galilean satellites, are the four largest moons of Jupiter. They are, in descending-size order, Ganymede (moon), Ganymede, Callisto (moon), Callisto, Io (moon), Io, and Europa (moon), Europa. They are the most apparent m ...
. It is located on Io's leading hemisphere at .
The volcano is responsible for the largest active lava flow in the entire Solar System, with recent flows dwarfing those of even other volcanos on Io.
The volcano was first observed in images acquired by the ''
Voyager 1
''Voyager 1'' is a space probe launched by NASA on September 5, 1977, as part of the Voyager program to study the outer Solar System and the interstellar medium, interstellar space beyond the Sun's heliosphere. It was launched 16 days afte ...
'' spacecraft in March 1979.
Later that year, the
International Astronomical Union
The International Astronomical Union (IAU; , UAI) is an international non-governmental organization (INGO) with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and developmen ...
named this feature after a
Georgian fire god,
Amirani.
Composition and physical attributes
Amirani is about the same age as
Jupiter
Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a Jupiter mass, mass more than 2.5 times that of all the other planets in the Solar System combined a ...
, which is around 4.5 billion years old. It is surrounded by the
Gish Bar Patera.
Within the mountains of the crater, Amirani lies at the center of a frozen
sulphuric lava field that consists of a half-circle shaped, 37 kilometer wide volcanic pit, which is connected to a 330 kilometer compound lava flow by a narrow channel. The southern half of the Amirani flow field is surrounded by a white plume of bright
sulfuric dioxide (SO2) diffuse deposits composed of
basalt
Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...
and
silica
Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , commonly found in nature as quartz. In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and abundant f ...
, that freeze and fall to the ground during eruptions.
Eruptions
The recent lava flows observed by the
Galileo
Galileo di Vincenzo Bonaiuti de' Galilei (15 February 1564 – 8 January 1642), commonly referred to as Galileo Galilei ( , , ) or mononymously as Galileo, was an Italian astronomer, physicist and engineer, sometimes described as a poly ...
appeared to have covered about 620 square kilometers of Io in less than five months, which was almost 6 times greater than
Hawaii
Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...
an volcano
Kīlauea
Kīlauea ( , ) is an active shield volcano in the Hawaiian Islands. It is located along the southeastern shore of Hawaii (island), Hawaii Island. The volcano is between 210,000 and 280,000 years old and grew above sea level about 100,000 years ...
covered in the span of 21 years. This volcano takes on characteristics of a
shield volcano
A shield volcano is a type of volcano named for its low profile, resembling a shield lying on the ground. It is formed by the eruption of highly fluid (low viscosity) lava, which travels farther and forms thinner flows than the more viscous lava ...
on Earth, in which its eruptions create
pahoehoe
Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or unde ...
-like lava flows and produce massive amounts of lava consisting of mainly basaltic material and sulfur. Its geological activity is created by the tidal forces brought on by Jupiter. Amirani's eruptions are controlled by the orbit which Io takes around Jupiter. The volcano erupts at temperatures of up to 1,650 degrees Celsius on to the surface of Io, which has an average temperature of negative 95 degrees Celsius. Unlike volcanoes on Earth, Amirani can erupt for years at a time with constant lava flows pouring out onto Io's surface.
Origin of name
The volcano was named
Amirani after the Georgian mythical hero from 3,000 to 2,000 BC. Amirani was considered the equivalent of
Prometheus
In Greek mythology, Prometheus (; , , possibly meaning "forethought")Smith"Prometheus". is a Titans, Titan. He is best known for defying the Olympian gods by taking theft of fire, fire from them and giving it to humanity in the form of technol ...
, the
Greek Titan, which is also the name of another volcano on Io. It is said that Amirani, son of
Dali
Dali or DALI may refer to:
Art and popular culture
* Dali, a location in ''Final Fantasy IX''
* ''Dali'' (Dalida album) (1984)
* ''Dali'' (Ali Project album) (1994)
* Espace Dalí, Salvador Dalí's permanent exhibition in France
Religion
...
, the great Goddess of the hunt, defied God by introducing the use of metal to all whom he came in contact with. Amirani's punishment was that he was to be chained on to the
Caucasus
The Caucasus () or Caucasia (), is a region spanning Eastern Europe and Western Asia. It is situated between the Black Sea and the Caspian Sea, comprising parts of Southern Russia, Georgia, Armenia, and Azerbaijan. The Caucasus Mountains, i ...
cliffs and left for dead. As Amirani struggled to free himself, an eagle attacked his liver every day.
References
Further reading
*
{{Io
Volcanoes of Io (moon)
Active volcanoes