ВНИМАНИЕ! На форуме начался конкурс - астрофотография месяца АПРЕЛЬ!
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Скорость вращения Меркурия вокруг своей оси почти постоянна, а скорость орбитального движения изменяется за счет большого эксцентриситета орбиты
чтобы там дневные и ночные температуры окружающего грунта отличались не более чем на градусов 50. И какой тогда будет средняя температура этого окружающего грунта..?
Интересно. На сколько метров надо закопать базу в Меркурий (на экваторе), чтобы там дневные и ночные температуры окружающего грунта отличались не более чем на градусов 50. И какой тогда будет средняя температура этого окружающего грунта..?
Меркурий - почти синхронизирован и день и ночь там только в узкой полосе либрации
Меркурий синхронизирован не 1:1, а 2:3, так что прогревается он весь
Цитата: Андрей Астрофизический от 21 Мар 2019 [04:44:17]Интересно. На сколько метров надо закопать базу в Меркурий (на экваторе), чтобы там дневные и ночные температуры окружающего грунта отличались не более чем на градусов 50. И какой тогда будет средняя температура этого окружающего грунта..?Из вики:"Поверхность планеты быстро нагревается и остывает, но уже на глубине в 1 м суточные колебания перестают ощущаться, а температура становится стабильной, равной приблизительно +75 °C[77]."Жарковато, без кондея не обойтись.
про температуру же - ну альбедо, уровень освещённости и считайте (даже и без расчёта - получится очень много, Солнце близко, не?)
вы параметры тел ........... вообще смотрите прежде чем писать?
"Поверхность планеты быстро нагревается и остывает, но уже на глубине в 1 м суточные колебания перестают ощущаться, а температура становится стабильной, равной приблизительно +75 °C[77].
Цитата: SpaceEngineer от 21 Мар 2019 [14:08:42]"Поверхность планеты быстро нагревается и остывает, но уже на глубине в 1 м суточные колебания перестают ощущаться, а температура становится стабильной, равной приблизительно +75 °C[77].Взято отсюда: Что есть что. Планеты. Меркурий. — Москва: Слово/Slovo, 2000.По мне этот источник не стоит доверия.
ну всё-таки веный день и вечная тень там есть, как тут посмотрел. перепад температур тоже впечатляет...
On November 29, 2012, NASA confirmed that images from MESSENGER had detected that craters at the north pole contained water ice. MESSENGER's principal investigator Sean Solomon is quoted in The New York Times estimating the volume of the ice to be large enough to "encase Washington, D.C., in a frozen block two and a half miles deep".[62][c]If the area of Washington is about 177 km2 and 2.5 miles is taken to equal 4 km, Solomon's estimate would equal about 700 cubic kilometres of ice, which would have a mass of about 600 billion tons (6×10^14 kg).Chang, Kenneth (November 29, 2012). "On Closest Planet to the Sun, NASA Finds Lots of Ice". The New York Times. p. A3. Archived from the original on November 29, 2012.
Там тоже упоминалось 75С. Но из контекста подразумевалась температура на глубине более метра вблизи экватора!
У Меркурия полноценные солнечные сутки, пусть и на 2 порядка длиннее земных.
600 миллиардов тонн воды на Северном полюсе Меркурия в виде льда.
Поверхность планеты быстро нагревается и остывает, но уже на глубине в 1 м суточные колебания перестают ощущаться, а температура становится стабильной
далеко от почти да, дамал больше, но и от полноценных суток тоже
59
ну когда слово "почти" не замечается, конечно многое можно выдать. 2/3 далеко от почти да, дамал больше, но и от полноценных суток тоже
и день и ночь там только в узкой полосе либрации,
Цитата: дерево от 21 Мар 2019 [22:07:04]У Меркурия полноценные солнечные сутки, пусть и на 2 порядка длиннее земных.59 это не совсем два порядка, ну когда слово "почти" не замечается, конечно многое можно выдать. 2/3 далеко от почти да, дамал больше, но и от полноценных суток тожеЦитата: crazy_terraformer от 21 Мар 2019 [22:45:06]600 миллиардов тонн воды на Северном полюсе Меркурия в виде льда.про эту воду уже слышал, правда как они оценили там глубину ещё и среднюю не очень ясно, а откуда ссылка?
Mercury GeologyVolcanism, tectonic faults, rock types and other topics related to the surface of the planet (кликните для показа/скрытия)I have a homework assignment that I am doing for my Astronomy class. And the question for the assignment is What are the three pieces of evidence that water exists in permanently shadowed polar craters on Mercury? If any one can help me out or let me know references I would greatly appreciate it. Thank you. - submitted by Vito Palmisano, College student, 04-22-2016You can start by looking at the list of Top Ten Science Results from MESSENGER, and scrolling to #2.Here are some references:Lawrence, D. J. et al., Evidence for water ice near Mercury's north pole from MESSENGER Neutron Spectrometer measurements, Science, 339, 292-296, 2013.Neumann, G. A., et al., Bright and dark polar deposits on Mercury: Evidence for surface volatiles, Science, 339, 296-300, 2013.Paige, D. A. et al., Thermal stability of volatiles in the north polar region of Mercury, Science, 339, 300-303, 2013.Chabot, N. L., et al., Craters hosting radar-bright deposits in Mercury's north polar region: Areas of persistent shadow determined from MESSENGER images, Journal of Geophysical Research: Planets, 118, 26-36, 10.1029/2012JE004172, 2013.Chabot, N. L., et al., Images of surface volatiles in Mercury's polar craters acquired by the MESSENGER spacecraft, Geology, 42, 1051-1054, 2014.Harmon, J.K., and Slade, M.A., 1992, Radar mapping of Mercury: Full-disk images and polar anomalies: Science, v. 258, p. 640–643, doi:10.1126 /science .258.5082.640.Harmon, J.K., Slade, M.A., and Rice, M.S., 2011, Radar imagery of Mercury's putative polar ice: 1999–2005 Arecibo results: Icarus, v. 211, p. 37–50, doi:10.1016/j.icarus.2010.08.007.-- Dave Blewett, Johns Hopkins University Applied Physics LaboratoryMESSENGER Participating ScientistI read at http://phys.org/news/2015-04-nasa-spacecraft-unprecedented-success-mercury.html, that there is enough hidden ice in Mercury's polar craters, to cover Washington (presumably state, not DC, though not specified which) more than two miles thick. Is this amount correct? Ca. 600,000 km^3? If so, then perhaps even Mercury might have some biological potential, especially if there is any geothermal heat. - submitted by Tatiana Covington, Interested public, 04-23-2015Analysis of data from MESSENGER's Neutron Spectrometer related to the abundance of hydrogen in Mercury's polar regions was reported in a paper by David Lawrence and colleagues in the journal Science in 2013 (volume 339, pages 292-296). The data are consistent with hydrogen (in the form of water ice) within permanently shadowed craters at the north and south poles. The presence of water ice within permanent polar shadows has been suspected since Earth-based radar measurements in the 1990s that found that polar craters have unusual radar reflectivity that is suggestive of ice. Additional evidence for ice in polar craters comes from models of the temperatures within the shadowed polar craters (indicating that water ice should be stable over billions of years), and measurements of the reflectivity of crater interiors by the MESSENGER laser altimeter. The reflectivity maps show areas of high and lower reflectance that can be explained by the presence of surface frosts in some areas, while other areas are covered by dark material, likely to be carbonaceous matter delivered by the same comet and asteroid impacts that brought the water. (кликните для показа/скрытия)November 29, 2012MESSENGER Finds New Evidence for Water Ice at Mercury's Poles New observations by the MESSENGER spacecraft provide compelling support for the long-held hypothesis that Mercury harbors abundant water ice and other frozen volatile materials in its permanently shadowed polar craters.Three independent lines of evidence support this conclusion: the first measurements of excess hydrogen at Mercury's north pole with MESSENGER's Neutron Spectrometer, the first measurements of the reflectance of Mercury's polar deposits at near-infrared wavelengths with the Mercury Laser Altimeter (MLA), and the first detailed models of the surface and near-surface temperatures of Mercury's north polar regions that utilize the actual topography of Mercury's surface measured by MLA. These findings are presented in three papers published online today in Science Express.Given its proximity to the Sun, Mercury would seem to be an unlikely place to find ice. But the tilt of Mercury's rotational axis is almost zero -- less than one degree -- so there are pockets at the planet's poles that never see sunlight. Scientists suggested decades ago that there might be water ice and other frozen volatiles trapped at Mercury's poles.The idea received a boost in 1991, when the Arecibo radio telescope in Puerto Rico detected unusually radar-bright patches at Mercury's poles, spots that reflected radio waves in the way one would expect if there were water ice. Many of these patches corresponded to the location of large impact craters mapped by the Mariner 10 spacecraft in the 1970s. But because Mariner saw less than 50 percent of the planet, planetary scientists lacked a complete diagram of the poles to compare with the images.MESSENGER's arrival at Mercury last year changed that. Images from the spacecraft's Mercury Dual Imaging System taken in 2011 and earlier this year confirmed that radar-bright features at Mercury's north and south poles are within shadowed regions on Mercury's surface, findings that are consistent with the water-ice hypothesis.Now the newest data from MESSENGER strongly indicate that water ice is the major constituent of Mercury's north polar deposits, that ice is exposed at the surface in the coldest of those deposits, but that the ice is buried beneath an unusually dark material across most of the deposits, areas where temperatures are a bit too warm for ice to be stable at the surface itself.MESSENGER uses neutron spectroscopy to measure average hydrogen concentrations within Mercury's radar-bright regions. Water ice concentrations are derived from the hydrogen measurements. "The neutron data indicate that Mercury's radar-bright polar deposits contain, on average, a hydrogen-rich layer more than tens of centimeters thick beneath a surficial layer 10 to 20 centimeters thick that is less rich in hydrogen," writes David Lawrence, a MESSENGER Participating Scientist based at the Johns Hopkins University Applied Physics Laboratory and the lead author of one of the papers. "The buried layer has a hydrogen content consistent with nearly pure water ice."Data from MESSENGER's Mercury Laser Altimeter (MLA) -- which has fired more than 10 million laser pulses at Mercury to make detailed maps of the planet's topography -- corroborate the radar results and Neutron Spectrometer measurements of Mercury's polar region, writes Gregory Neumann of the NASA Goddard Flight Center. In a second paper, Neumann and his colleagues report that the first MLA measurements of the shadowed north polar regions reveal irregular dark and bright deposits at near-infrared wavelength near Mercury's north pole."These reflectance anomalies are concentrated on poleward-facing slopes and are spatially collocated with areas of high radar backscatter postulated to be the result of near-surface water ice," Neumann writes. "Correlation of observed reflectance with modeled temperatures indicates that the optically bright regions are consistent with surface water ice."The MLA also recorded dark patches with diminished reflectance, consistent with the theory that the ice in those areas is covered by a thermally insulating layer. Neumann suggests that impacts of comets or volatile-rich asteroids could have provided both the dark and bright deposits, a finding corroborated in a third paper led by David Paige of the University of California, Los Angeles.Paige and his colleagues provided the first detailed models of the surface and near-surface temperatures of Mercury's north polar regions that utilize the actual topography of Mercury's surface measured by MLA. The measurements "show that the spatial distribution of regions of high radar backscatter is well matched by the predicted distribution of thermally stable water ice," he writes.According to Paige, the dark material is likely a mix of complex organic compounds delivered to Mercury by the impacts of comets and volatile-rich asteroids, the same objects that likely delivered water to the innermost planet. The organic material may have been darkened further by exposure to the harsh radiation at Mercury's surface, even in permanently shadowed areas.This dark insulating material is a new wrinkle to the story, says Sean Solomon of the Columbia University's Lamont-Doherty Earth Observatory, principal investigator of the MESSENGER mission. "For more than 20 years the jury has been deliberating on whether the planet closest to the Sun hosts abundant water ice in its permanently shadowed polar regions. MESSENGER has now supplied a unanimous affirmative verdict.""But the new observations have also raised new questions," adds Solomon. "Do the dark materials in the polar deposits consist mostly of organic compounds? What kind of chemical reactions has that material experienced? Are there any regions on or within Mercury that might have both liquid water and organic compounds? Only with the continued exploration of Mercury can we hope to make progress on these new questions."MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) is a NASA-sponsored scientific investigation of the planet Mercury and the first space mission designed to orbit the planet closest to the Sun. The MESSENGER spacecraft launched on August 3, 2004, and entered orbit about Mercury on March 17, 2011 (March 18, 2011 UTC), to begin a yearlong study of its target planet. MESSENGER's extended mission began on March 18, 2012. Dr. Sean C. Solomon, the director of Columbia University's Lamont-Doherty Earth Observatory, leads the mission as Principal Investigator. The Johns Hopkins University Applied Physics Laboratory built and operates the MESSENGER spacecraft and manages this Discovery-class mission for NASA. The paper by Lawrence and colleagues estimated that the total amount of polar ice is in the range 2.1 × 10^16 to 1.4 x 10^18 grams. One gram of ice has a volume of about 1 centimeter cubed, so you can compute for yourself the thickness that this amount would reach if placed uniformly over a given area. With both water and organic material present, Mercury's poles would be an interesting place to study pre-biotic material and the history of the delivery of water and organics to the inner solar system.--Dave Blewett, Johns Hopkins University Applied Physics LaboratoryMESSENGER Participating ScientistIt's amazing how Mercury could be deposits of ice in areas of permanent shadow. When this world is too near the Sun. No doubt this is weird, but possible, giving rise to many questions about the possibility to exist in your sub. Soil deposits unfrozen water, a hypothesis to be considered by the investigators, even a very remote possibility in credible. Has another aspect, despite Mercury being constantly bombarded by intense solar radiation,, it may contain certain elements, such as metals and crystals, in various forms, which may actually be useful to man and Industry, mainly in its sobsllol. This hypothesis should be viewed, analyzed. Mercury has Unique features in our Solar System, being a planet that is essentially under the action of the gravitational field of the sun, not to mention the intense radiation that bombards the planet because it is too close to the Sun. The Departure seems to be a world completely without any chance of Sterile Organic contain elements due to its proximity to the Sun, but the latest investigations that have been made, so why is not found something that can be dry ice, or something similar. Hopefully soon to have more concrete results of the discoveries made in Mercury. - submitted by Luiza Martins, 10-23-2014The idea of ice existing in areas of permanent shadow was first proposed in the early 1960s (for polar craters on the Moon). The first evidence for polar ice on Mercury came from observations using Earth-based radar in the early 1990s. New evidence for water ice in Mercury polar shadows came from MESSENGER in 2012: neutron spectrometer measurements of enhanced hydrogen abundance, laser altimeter detection of bright spots in polar craters that is likely to be surface frost, and thermal modeling that shows that the temperatures in the polar permanent shadows are right for water ice to be stable for long periods of time. Refer to this previous question for more about those results.The recent publication of MDIS images that use long exposures to provide a view within areas of shadow are yet further evidence that water ice exists in these locations. The majority of the evidence suggests that the material in the polar shadows is water ice, rather than some other compound. For example, if the material was carbon dioxide ice (CO2), then there would not be a hydrogen enhancement as is observed by the MESSENGER neutron spectrometer. On Earth, many useful deposits of metals (ore deposits) were formed by hydrothermal processes, involving extensive chemical reactions in the subsurface by heated water flowing through pore spaces and fractures. Mercury is very unlikely to have abundant liquid water in the subsurface. However, some interesting chemistry may be taking place between ice in the permanent shadow and the host rocks and soils. In fact, in shadowed locations that are just a bit too warm for water ice to be stable on the surface, MLA and MDIS find evidence for the presence of dark carbonaceous compounds, likely delivered by comets.--Dave Blewett, Johns Hopkins University Applied Physics LaboratoryMESSENGER Participating Scientist
Но остаются ли кратеры неподвижными или может существовать некоторый дрейф коры ?
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Тема: Освоение Меркурия (Прочитано 21620 раз)
