Palus Somni (

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

''palūs somnī'' "Marsh of Sleep") is an area on the

Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...

of relatively level but somewhat uneven terrain that lies along the northeastern edge of

Mare Tranquillitatis Mare Tranquillitatis (Latin ''tranquillitātis'', the Sea of Tranquillity or Sea of Tranquility; see spelling differences) is a lunar mare that sits within the Tranquillitatis basin on the Moon. It is the first location on another world to be ...

and the Sinus Concordiae. It has

selenographic coordinates The selenographic coordinate system is used to refer to locations on the surface of Earth's moon. Any position on the lunar surface can be referenced by specifying two numerical values, which are comparable to the latitude and longitude of Earth. ...

14.1° N, 45.0° E, and has a diameter of 163 km. Aldo Ferruggia - Proclus crater

The surface of this feature has low ridges and patches of level terrain. It has a higher

albedo Albedo (; ) is the measure of the diffuse reflection of solar radiation out of the total solar radiation and measured on a scale from 0, corresponding to a black body that absorbs all incident radiation, to 1, corresponding to a body that refl ...

than the

lunar mare The lunar maria (; singular: mare ) are large, dark, basaltic plains on Earth's Moon, formed by ancient asteroid impacts on the far side on the Moon that triggered volcanic activity on the opposite (near) side. They were dubbed , Latin for 'seas' ...

to the west, and is a shade of grey typical of continental terrain. A few minor craters lie within its borders, with the flooded Lyell along the west edge, Crile to the east, and Franz to the northwest. The bright crater Proclus is to the northeast. In 1907 it was described as having "a color which is unique upon the moon, a kind of light brown, quite unlike the hue of any of the other plains or mountain regions"Serviss, Garrett P.: ''The Moon.'' 1907.

References

{{Lunar maria Somni, Palus