Mare Humboldtianum

Mare Humboldtianum is a lunar mare situated near the northeastern limb of the Moon, immediately east of Mare Frigoris. The feature occupies the central part of the much larger Humboldtianum basin, an ancient impact structure whose outer basin extends for more than 600 kilometres. The mare itself reaches a maximum dimension of approximately 230 kilometres and is centred at about 56.9° north latitude and 81.5° east longitude. The feature lies across the boundary between the Moon's near side and far side. As a result, its visibility from Earth varies with lunar libration: under favourable viewing conditions observers can see it near the eastern limb, while at other times portions or all of the mare may be hidden beyond the apparent edge of the lunar disk. The basin rim forms a broad mountain system that is particularly conspicuous under oblique illumination. Within the basin, a lighter-toned area to the southeast of the darker mare deposits consists of hilly terrain rather than a uniform basaltic plain. Geologically, the Humboldtianum basin material is assigned to the Nectarian period, while the mare deposits are associated with the Upper Imbrian epoch. The basaltic material is estimated to have formed roughly 3.4 to 3.7 billion years ago. The northwestern portion of the mare is overlain by or connected with the walled plain Bel'kovich, and the flooded crater Bel'kovich A crosses the southwestern rim of Bel'kovich and extends onto part of the mare floor. A mascon, or concentration of mass producing a local gravitational anomaly, is located near the centre of the Humboldtianum basin. Its presence was identified through Doppler tracking of NASA's Lunar Prospector spacecraft. The combination of the basin's great size, its limb location, and its mixture of near-side and far-side terrain makes Mare Humboldtianum an important object for lunar geology and cartography. The name means approximately "Sea of Alexander von Humboldt." It was assigned by the German selenographer Johann Mädler in honour of the explorer and naturalist Alexander von Humboldt. Mare Humboldtianum is one of only two lunar maria named for people; the other is Mare Smythii, named for the British astronomer William Henry Smyth. The feature has also appeared in popular culture, including an episode of the 1967 television series Captain Scarlet and the Mysterons, which depicted a Mysteron outpost in the Humboldt Sea.

Mare Humboldtianum is a basalt-filled lunar mare located within the Humboldtianum impact basin on the northeastern edge of the Moon. Its setting is unusual because the basin crosses the transition between the lunar near side and far side. From Earth, the mare is therefore subject to the effects of libration and may not always be visible. The feature is centred near 56.9° N, 81.5° E, and the mare deposits span up to approximately 230 kilometres, while the surrounding basin is more than 600 kilometres across. The name was given by the German selenographer Johann Mädler in recognition of Alexander von Humboldt, the nineteenth-century explorer and naturalist. The designation refers to a lunar "sea," following the historical naming convention in which dark basaltic plains were thought to be bodies of water. Mare Humboldtianum is notable as one of only two lunar maria named after individuals, the other being Mare Smythii, which honours British astronomer William Henry Smyth. The geological history of the region begins with the formation of the Humboldtianum basin during the Nectarian period. Later volcanic flooding produced the darker mare material, which is assigned to the Upper Imbrian epoch and is estimated to be about 3.4 to 3.7 billion years old. The basin's interior is not uniform: a relatively light region to the southeast of the mare is composed of hills, while the basin rim forms a mountainous ring that becomes easier to identify under low-angle sunlight. Several named features intersect or adjoin the mare. Bel'kovich, a large walled plain, occupies the northwestern part of the basin and extends over the northwestern portion of the mare. The flooded crater Bel'kovich A crosses the southwestern rim of Bel'kovich and reaches onto the mare floor. These overlapping structures provide evidence of the complex sequence of impacts, volcanic flooding, and later modification that shaped the basin. A central mascon was detected through Doppler tracking of the Lunar Prospector spacecraft. The gravitational high indicates an anomalous concentration of mass beneath the basin, consistent with the geological structure of a large impact basin partly filled by dense volcanic material. Modern lunar orbital imaging and geological mapping have continued to refine understanding of the basin, its deposits, and its surface relationships. Mare Humboldtianum has also acquired a limited place in popular culture. The 1967 television series Captain Scarlet and the Mysterons identified the Humboldt Sea as the location of a fictional Mysteron outpost. This fictional use is separate from the feature's scientific and cartographic identity.

• 2017

  Geological mapping of the Humboldtianum basin

  [3]49th Lunar and Planetary Science Conferencehou.usra.edu

  A Lunar and Planetary Science Conference contribution presented geological mapping of the Humboldtianum basin and its deposits.

• 2010

  Lunar Reconnaissance Orbiter Camera region of interest

  [2]Lunar Reconnaissance Orbiter Cameralroc.asu.edu

  The Lunar Reconnaissance Orbiter Camera project published a region-of-interest article concerning Mare Humboldtianum and its surrounding terrain.

• Name assigned in honour of Alexander von Humboldt

  [1]Mare Humboldtianumen.wikipedia.org

  Johann Mädler named the lunar mare for Alexander von Humboldt, linking the feature to the tradition of naming dark lunar plains as maria.

• Central mascon identified

  [1]Mare Humboldtianumen.wikipedia.org

  Doppler tracking of NASA's Lunar Prospector spacecraft revealed a mass concentration near the centre of the Humboldtianum basin.

A formally named lunar geographic and geological feature, rather than a commercial brand or product.

1. 1Mare Humboldtianumen.wikipedia.org
2. 2Lunar Reconnaissance Orbiter Cameralroc.asu.edu
3. 349th Lunar and Planetary Science Conferencehou.usra.edu