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Hun Kal (crater)
Encyclopedia
Hun Kal is a small crater
on Mercury
that serves as the reference point for the planet's system of longitude
. The longitude of Hun Kal's center is defined as being 20° W, thus establishing the planet's prime meridian
.
Hun Kal was chosen as a reference point since the actual prime meridian was in shadow when Mariner 10
photographed the region, hiding any features near 0° longitude from view.
Hun Kal is about 1.5 km in diameter.
The name "Hun Kal" means '20' in the language of the Maya
.
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...
on Mercury
Mercury (planet)
Mercury is the innermost and smallest planet in the Solar System, orbiting the Sun once every 87.969 Earth days. The orbit of Mercury has the highest eccentricity of all the Solar System planets, and it has the smallest axial tilt. It completes three rotations about its axis for every two orbits...
that serves as the reference point for the planet's system of longitude
Longitude
Longitude is a geographic coordinate that specifies the east-west position of a point on the Earth's surface. It is an angular measurement, usually expressed in degrees, minutes and seconds, and denoted by the Greek letter lambda ....
. The longitude of Hun Kal's center is defined as being 20° W, thus establishing the planet's prime meridian
Prime Meridian
The Prime Meridian is the meridian at which the longitude is defined to be 0°.The Prime Meridian and its opposite the 180th meridian , which the International Date Line generally follows, form a great circle that divides the Earth into the Eastern and Western Hemispheres.An international...
.
Hun Kal was chosen as a reference point since the actual prime meridian was in shadow when Mariner 10
Mariner 10
Mariner 10 was an American robotic space probe launched by NASA on November 3, 1973, to fly by the planets Mercury and Venus. It was launched approximately two years after Mariner 9 and was the last spacecraft in the Mariner program...
photographed the region, hiding any features near 0° longitude from view.
Hun Kal is about 1.5 km in diameter.
The name "Hun Kal" means '20' in the language of the Maya
Mayan languages
The Mayan languages form a language family spoken in Mesoamerica and northern Central America. Mayan languages are spoken by at least 6 million indigenous Maya, primarily in Guatemala, Mexico, Belize and Honduras...
.