Poincaré is a large
lunar impact basin that lies in the southern
hemisphere
Hemisphere may refer to:
In geometry
* Hemisphere (geometry), a half of a sphere
As half of Earth or any spherical astronomical object
* A hemisphere of Earth
** Northern Hemisphere
** Southern Hemisphere
** Eastern Hemisphere
** Western Hemi ...
on the
far side of the
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 ...
. Most of the formation has been heavily eroded by subsequent impacts, leaving a battered formation with only rugged remnants of the original outer rim to the west.
The eastern half has been completely worn away, and much of the interior has been resurfaced by
lava
Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a Natural satellite, moon onto its surface. Lava may be erupted at a volcano or through a Fissure vent, fractu ...
flows. This surface has a lower
albedo
Albedo ( ; ) is the fraction of sunlight that is Diffuse reflection, diffusely reflected by a body. It is measured on a scale from 0 (corresponding to a black body that absorbs all incident radiation) to 1 (corresponding to a body that reflects ...
than the surrounding terrain, giving it a dark appearance. A rugged formation forms a low north–south range across the eastern section of the floor, possibly the remnant of an inner ring.
The perimeter of Poincaré has several notable craters. To the north is the crater
Hopmann, while the craters
Abbe and
Hess lie to the east. Directly to the west is
Planck, a walled plain of similar dimensions to Poincaré. Both formations are sufficiently large to have formed a small
lunar mare
The lunar maria ( ; mare ) are large, dark, basaltic plains on Earth's Moon, formed by lava flowing into ancient impact basins. They are less reflective than the "highlands" as a result of their iron-rich composition, and hence appear dark to ...
on the near side face of the Moon.
The basin's name was adopted in 1970 by the
IAU
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 ...
.
Poincaré
Gazetteer of Planetary Nomenclature International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (WGPSN)
Satellite craters
By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Poincaré.
References
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{{DEFAULTSORT:Poincare
Impact craters on the Moon
Crater