Hokusai (crater)
Encyclopedia
Hokusai is a rayed impact crater
on Mercury
, which was discovered in 1991 by ground based radar
observations conducted in the Goldstone Observatory. The crater was initially known as the feature B. Its appearance was so dissimilar to other impact craters that it once was thought to be a shield volcano
. However improved radar images by the Arecibo Observatory
obtained later in 2000–2005 clearly showed that the feature B is an impact crater having an extensive ray system. The bright appearance of rays in the radio images indicates that the crater is geologically young as the fresh impact ejecta has rough surface, which is a good scatterer of radio waves.
Hokusai is named after Katsushika Hokusai (1760–1849), a Japanese artist and printmaker of the Edo period
. The name Hokusai was suggested by radar astronomer John K. Harmon. It has the diameter of about 95 km (or 110 km), while the rays extend thousands kilometers from it covering much of the northern hemisphere.
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...
, which was discovered in 1991 by ground based radar
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...
observations conducted in the Goldstone Observatory. The crater was initially known as the feature B. Its appearance was so dissimilar to other impact craters that it once was thought to be a shield volcano
Shield volcano
A shield volcano is a type of volcano usually built almost entirely of fluid lava flows. They are named for their large size and low profile, resembling a warrior's shield. This is caused by the highly fluid lava they erupt, which travels farther than lava erupted from more explosive volcanoes...
. However improved radar images by the Arecibo Observatory
Arecibo Observatory
The Arecibo Observatory is a radio telescope near the city of Arecibo in Puerto Rico. It is operated by SRI International under cooperative agreement with the National Science Foundation...
obtained later in 2000–2005 clearly showed that the feature B is an impact crater having an extensive ray system. The bright appearance of rays in the radio images indicates that the crater is geologically young as the fresh impact ejecta has rough surface, which is a good scatterer of radio waves.
Hokusai is named after Katsushika Hokusai (1760–1849), a Japanese artist and printmaker of the Edo period
Edo period
The , or , is a division of Japanese history which was ruled by the shoguns of the Tokugawa family, running from 1603 to 1868. The political entity of this period was the Tokugawa shogunate....
. The name Hokusai was suggested by radar astronomer John K. Harmon. It has the diameter of about 95 km (or 110 km), while the rays extend thousands kilometers from it covering much of the northern hemisphere.