Mare Marginis
Encyclopedia
Mare Marginis is a lunar mare
that lies on the very edge of the lunar nearside. The selenographic coordinates of this feature are 13.3° N, 86.1° E, and the diameter is 420 km. The name is Latin
for "Sea of the Edge".
This mare differs from most of the nearside maria; it has an irregular outline and it appears to be fairly thin. It has small circular and elongated features in the mare plains that
probably mark impact crater
s buried by less than 1000 to 1700 feet of lava
. Further, Mare Marginis is not centered on any clear, large impact basin. Thus, Mare Marginis seems to mark a low-lying region of the highlands where mare lavas were just able to reach the surface. Several large mare-floored craters also occur nearby. In these craters, the crater floors lie below the surrounding highland surface. Thus, they mark sites around Mare Marginis where lavas were close to the lunar surface. The major crater
to the north of Marginis is Al-Biruni
, with Ibn Yunus
to the southeast and Goddard
to the northwest.
The surface of this mare displays some swirling, higher albedo
deposits that are similar to the Reiner Gamma
feature on the Oceanus Procellarum
. This feature is associated with a relatively strong magnetic field
. It is also located at the antipode
of the Mare Orientale
impact basin, and may be associated with the formation of that feature. Other possible explanations for the formation include a comet
ary impact, venting of volcanic gases, or just normal surface markings that are shielded from space weathering due to the magnetic field. But the exact cause of albedo features such as this remain a mystery for future solution.
Lunar mare
The lunar maria are large, dark, basaltic plains on Earth's Moon, formed by ancient volcanic eruptions. They were dubbed maria, Latin for "seas", by early astronomers who mistook them for actual seas. They are less reflective than the "highlands" as a result of their iron-rich compositions, and...
that lies on the very edge of the lunar nearside. The selenographic coordinates of this feature are 13.3° N, 86.1° E, and the diameter is 420 km. The name is Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
for "Sea of the Edge".
This mare differs from most of the nearside maria; it has an irregular outline and it appears to be fairly thin. It has small circular and elongated features in the mare plains that
probably mark 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...
s buried by less than 1000 to 1700 feet of lava
Lava
Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...
. Further, Mare Marginis is not centered on any clear, large impact basin. Thus, Mare Marginis seems to mark a low-lying region of the highlands where mare lavas were just able to reach the surface. Several large mare-floored craters also occur nearby. In these craters, the crater floors lie below the surrounding highland surface. Thus, they mark sites around Mare Marginis where lavas were close to the lunar surface. The major crater
to the north of Marginis is Al-Biruni
Al-Biruni (crater)
Al-Biruni is an impact crater that lies on the far side of the Moon, just beyond the eastern limb. This portion of the surface is sometimes brought into sight due to librations of the Moon, but due to its location the crater is viewed from the side...
, with Ibn Yunus
Ibn Yunus (crater)
Ibn Yunus is the remains of a flooded lunar crater. It lies on the far side of the Moon, just past the eastern limb. It can only be viewed from Earth under conditions of favorable libration and lighting, and even then it is seen from the edge. This feature is attached to the east-southeastern outer...
to the southeast and Goddard
Goddard (crater)
Goddard is a lunar crater that is located along the eastern limb of the Moon, and so is visible from the edge from Earth. It is best viewed during favorable librations when the orientation of the Moon brings it further into sight. The crater is located in the Mare Marginis, to the northeast of the...
to the northwest.
The surface of this mare displays some swirling, higher albedo
Albedo
Albedo , or reflection coefficient, is the diffuse reflectivity or reflecting power of a surface. It is defined as the ratio of reflected radiation from the surface to incident radiation upon it...
deposits that are similar to the Reiner Gamma
Reiner Gamma
Reiner Gamma is an albedo feature that is located on the Oceanus Procellarum, to the west of the crater Reiner on the Moon. The center of the formation is located at selenographic coordinates . It has an overall dimension of about 70 kilometres...
feature on the Oceanus Procellarum
Oceanus Procellarum
Oceanus Procellarum is a vast lunar mare on the western edge of the near side of the Earth's Moon. Its name derives from the old superstition that its appearance during the second quarter heralded bad weather...
. This feature is associated with a relatively strong magnetic field
Magnetic field
A magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;...
. It is also located at the antipode
Antipode
Antipode, Antipodes, or Antipodeans may refer to:* Antipodal point, the diametrically opposite point on a sphere* Antipodes Water Company, a premium bottled water brand...
of the Mare Orientale
Mare Orientale
Mare Orientale is one of the most striking large scale lunar features, resembling a target ring bull's-eye. Located on the extreme western edge of the lunar nearside, this impact basin is difficult to see from an Earthbound perspective.Material from this basin was not sampled by the Apollo program...
impact basin, and may be associated with the formation of that feature. Other possible explanations for the formation include a comet
Comet
A comet is an icy small Solar System body that, when close enough to the Sun, displays a visible coma and sometimes also a tail. These phenomena are both due to the effects of solar radiation and the solar wind upon the nucleus of the comet...
ary impact, venting of volcanic gases, or just normal surface markings that are shielded from space weathering due to the magnetic field. But the exact cause of albedo features such as this remain a mystery for future solution.