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Malapert (crater)

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Malapert is a lunar impact crater that lies near the south pole of the Moon , named for 17th century astronomer Charles Malapert . From the Earth this formation is viewed from the side, limiting the amount of detail that can be seen. The crater is also illuminated at very low angles, so that parts of the interior remain in almost constant darkness . The nearest craters of note are Cabeus to the west, and Shoemaker to the south-southeast and nearer to the south pole of the Moon.

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78-458: The rim of Malapert forms an irregular ring of peaks around the interior floor. The western side of the rim is overlain by what appear to be impact craters. There are also small craters overlying the southeastern rim. Much of the interior and details of the rim remain hidden by shadows. The southwestern part of the rim forms part of a 5-km-high rise in the surface that has been unofficially designated Malapert Mountain . This ridge appears wider along

156-508: A binary planet , its centre of gravity is within Earth, about 4,671 km (2,902 miles) or 73.3% of the Earth's radius from the centre of the Earth. This centre of gravity remains on the line between the centres of the Earth and Moon as the Earth completes its diurnal rotation. The path of the Earth–Moon system in its solar orbit is defined as the movement of this mutual centre of gravity around

234-416: A diurnal libration , which allows one to view an additional one degree's worth of lunar longitude. For the same reason, observers at both of Earth's geographical poles would be able to see one additional degree's worth of libration in latitude. Besides these "optical librations" caused by the change in perspective for an observer on Earth, there are also "physical librations" which are actual nutations of

312-413: A massif . The rim is slightly raised about the surrounding surface and it has an outer rampart that has been only lightly impacted. No significant craters intersect the rim, and it is sloped about 1.5° toward the direction 50–90° from the Earth. The age of the crater is about 3.6 billion years and it has been in the proximity of the south lunar pole for at least the last two billion years. Because

390-493: A 34-kg probe made a hard landing near the crater. The Moon Impact Probe (MIP) was launched from the Indian Chandrayaan-1 spacecraft and reached the surface 25 minutes later. The probe carried a radar altimeter, video imaging system, and a mass spectrometer, which detected the presence of water during the descent. Some sites along Shackleton's rim receive almost constant illumination. At these locales sunlight

468-410: A commodity that is expensive to deliver directly from the Earth. This crater has also been proposed as a future site for a large infrared telescope . The low temperature of the crater floor makes it ideal for infrared observations, and solar cells placed along the rim could provide near-continuous power to the observatory. About 120 kilometers from the crater lies the 5-km tall Malapert Mountain ,

546-455: A line running roughly east–west, although details of the back side are hidden by shadows. The peak of this ridge lies almost exactly along 0° longitude, and it has the unusual attribute of lying within sight of both the Earth and the crater Shackleton at the south pole. Due to the location of Malapert Mountain, it has been proposed as the site of a transmitter for an expedition to the south lunar pole. The back side of this ridge also lies within

624-600: A location called "Shackleton Heights", where his album's back-story takes place. Shackleton was the landing site for the Korean movie The_Moon (2024 film) Orbit of the Moon The Moon orbits Earth in the prograde direction and completes one revolution relative to the Vernal Equinox and the stars in about 27.32 days (a tropical month and sidereal month ) and one revolution relative to

702-494: A long history. The orbit of the Moon is a nearly circular ellipse about Earth (the semimajor and semiminor axes are 384,400 km and 383,800 km, respectively: a difference of only 0.16%). The equation of the ellipse yields an eccentricity of 0.0549 and perigee and apogee distances of 362,600 km (225,300 mi) and 405,400 km (251,900 mi) respectively (a difference of 12%). Since nearer objects appear larger,

780-465: A mean orbital velocity around the barycentre between the Earth and the Moon, of 1.022 km/s (0.635 miles/s, 2,286 miles/h), the Moon covers a distance approximately its diameter, or about half a degree on the celestial sphere , each hour. The Moon differs from most regular satellites of other planets in that its orbit is closer to the ecliptic plane instead of its primary 's (in this case, Earth's) equatorial plane . The Moon's orbital plane

858-457: A peak that is perpetually visible from the Earth , and which could serve as a radio relay station when suitably equipped. In 2006, NASA named the rim of Shackleton as a potential candidate for its lunar outpost , originally slated to be up and running by 2020 and continuously staffed by a crew by 2024. The location would promote self-sustainability for lunar residents, as perpetual sunlight on

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936-402: A perspective effect which allows us to see up to eight degrees of longitude of its eastern (right) far side . Conversely, when the Moon reaches its apogee, its orbital motion is slower than its rotation, revealing eight degrees of longitude of its western (left) far side. This is referred to as optical libration in longitude . The Moon's axis of rotation is inclined by in total 6.7° relative to

1014-418: A well-defined geometric model of epicycles and evection . Isaac Newton was the first to develop a complete theory of motion, Newtonian mechanics . The observations of the lunar motion were the main test of his theory. There are several different periods associated with the lunar orbit. The sidereal month is the time it takes to make one complete orbit around Earth with respect to the fixed stars. It

1092-452: Is inclined by about 5.1° with respect to the ecliptic plane, whereas Earth's equatorial plane is tilted by about 23° with respect to the ecliptic plane . The properties of the orbit described in this section are approximations. The Moon's orbit around Earth has many variations ( perturbations ) due to the gravitational attraction of the Sun and planets, the study of which ( lunar theory ) has

1170-449: Is about 27.32 days. The synodic month is the time it takes the Moon to reach the same visual phase . This varies notably throughout the year, but averages around 29.53 days. The synodic period is longer than the sidereal period because the Earth–Moon system moves in its orbit around the Sun during each sidereal month, hence a longer period is required to achieve a similar alignment of Earth,

1248-479: Is almost always available for conversion into electricity using solar panels , potentially making them good locations for future Moon landings . The temperature at this site is also more favorable than at more equatorial latitudes as it does not experience the daily temperature extremes of 100 °C when the Sun is overhead, to as low as −150 °C during the lunar night. While scientific experiments performed by Clementine and Lunar Prospector could indicate

1326-471: Is called major lunar standstill . Around this time, the Moon's declination will vary from −28°36′ to +28°36′. Conversely, 9.3 years later, the angle between the Moon's orbit and Earth's equator reaches its minimum of 18°20′. This is called a minor lunar standstill . The last lunar standstill was a minor standstill in October 2015. At that time the descending node was lined up with the equinox (the point in

1404-474: Is covered by an uneven mound-like feature that is 300 to 400 m (980–1,310 ft) thick. The central peak is about 200 m (660 ft) in height. The continuous shadows in the south polar craters cause the floors of these formations to maintain a temperature that never exceeds about 100 K (−173 °C; −280 °F). For Shackleton, the average temperature was determined to be about 90 K (−183 °C; −298 °F), reaching 88 K at

1482-465: Is distinct from the nodal precession of its orbital plane and axial precession of the moon itself. The mean inclination of the lunar orbit to the ecliptic plane is 5.145°. Theoretical considerations show that the present inclination relative to the ecliptic plane arose by tidal evolution from an earlier near-Earth orbit with a fairly constant inclination relative to Earth's equator. It would require an inclination of this earlier orbit of about 10° to

1560-426: Is minor compared to the difference between lunar night and lunar day. At the lunar poles, instead of usual lunar days and nights of about 15 Earth days, the Sun will be "up" for 173 days as it will be "down"; polar sunrise and sunset takes 18 days each year. "Up" here means that the centre of the Sun is above the horizon. Lunar polar sunrises and sunsets occur around the time of eclipses (solar or lunar). For example, at

1638-426: Is not occurring fast enough for the rotation to lengthen to a month before other effects change the situation: approximately 2.3 billion years from now, the increase of the Sun's radiation will have caused Earth's oceans to evaporate, removing the bulk of the tidal friction and acceleration. The Moon is in synchronous rotation , meaning that it keeps the same face toward Earth at all times. This synchronous rotation

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1716-483: Is not universally agreed upon within the scientific community. Radar images of the crater at a wavelength of 13 cm show no evidence for water ice deposits. Optical imaging inside the crater was done for the first time by the Japanese lunar orbiter spacecraft Kaguya in 2007. It did not have any evidence of significant amount of water ice, down to the image resolution of 10 m per pixel. On November 15, 2008,

1794-430: Is only true on average because the Moon's orbit has a definite eccentricity. As a result, the angular velocity of the Moon varies as it orbits Earth and hence is not always equal to the Moon's rotational velocity which is more constant. When the Moon is at its perigee, its orbital motion is faster than its rotation. At that time the Moon is a bit ahead in its orbit with respect to its rotation about its axis, and this creates

1872-470: Is possible that the interior floor might not have collected a significant quantity of volatiles since its formation. However other craters in the vicinity are considerably older, and may contain significant deposits of hydrogen , possibly in the form of water ice. (See Shoemaker (lunar crater) , for example.) Radar studies preceding and following the Lunar Prospector mission demonstrate that

1950-464: Is that in the past the Earth rotated much faster, a day possibly lasting only 9 hours on the early Earth. The resulting tidal waves in the ocean would have then been much shorter and it would have been more difficult for the long wavelength tidal forcing to excite the short wavelength tides. The Moon is gradually receding from Earth into a higher orbit, and calculations suggest that this would continue for about 50 billion years. By that time, Earth and

2028-460: The Antarctic continent. From the perspective of the Earth , this crater lies along the southern limb of the Moon, making observation difficult. Detailed mapping of the polar regions and farside of the Moon did not occur until the advent of orbiting spacecraft. Shackleton lies entirely within the rim of the immense South Pole-Aitken basin , which is one of the largest known impact formations in

2106-587: The IM-1 mission, landed near Malapert-A in February 2024. By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Malapert. At a Space Resources Roundtable co-sponsored by the Lunar and Planetary Institute a presentation by B. L. Cooper underscored the difficulty of imaging terrain illuminated by high-incidence-angle light. Nonetheless,

2184-589: The Solar System . This basin is over 12 kilometers deep, and an exploration of its properties could provide useful information about the lunar interior. A neutron spectrometer on board the Lunar Prospector spacecraft detected enhanced concentrations of hydrogen close to the northern and southern lunar poles, including the crater Shackleton. At the end of this mission in July 1999, the spacecraft

2262-454: The Solar eclipse of March 9, 2016 , the Moon was near its descending node, and the Sun was near the point in the sky where the equator of the Moon crosses the ecliptic. When the Sun reaches that point, the centre of the Sun sets at the lunar north pole and rises at the lunar south pole. The solar eclipse of September 1 of the same year , the Moon was near its ascending node, and the Sun was near

2340-508: The Sun in about 29.53 days (a synodic month ). Earth and the Moon orbit about their barycentre (common centre of mass ), which lies about 4,670 km (2,900 miles) from Earth's centre (about 73% of its radius), forming a satellite system called the Earth–Moon system . On average, the distance to the Moon is about 384,400 km (238,900 mi) from Earth's centre, which corresponds to about 60 Earth radii or 1.282 light-seconds. With

2418-578: The alternate history television drama series For All Mankind . In the program, astronauts in a fictionalized version of the Apollo 15 mission land near Shackleton in 1971 and discover water ice in the crater walls. Later, the United States and the Soviet Union establish competing, crewed bases next to the crater to take advantage of the ice for drinking, oxygen and other uses. Shackleton

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2496-467: The lunar south pole . The peaks along the crater's rim are exposed to almost continual sunlight, while the interior is perpetually in shadow . The low-temperature interior of this crater functions as a cold trap that may capture and freeze volatiles shed during comet impacts on the Moon. Measurements by the Lunar Prospector spacecraft showed higher than normal amounts of hydrogen within

2574-473: The orbit of the Moon is tilted only 1.5° from the ecliptic , the interior of this crater lies in perpetual darkness. Estimates of the area in permanent shadow were obtained from Earth-based radar studies. Peaks along the rim of the crater are almost continually illuminated by sunlight, spending about 80–90% of each lunar orbit exposed to the Sun . Continuously illuminated mountains have been termed peaks of eternal light and have been predicted to exist since

2652-412: The radio shadow for transmissions from the Earth , and it has been suggested as a site for a radio telescope because the radio noise from Earth would be blocked. In July 2013, private company Moon Express released details of a mission they were planning for no earlier than 2018. The mission would land two telescopes on the Moon, with the preferred location of Malapert crater, to take advantage of

2730-419: The regolith to liberate significant quantities of water vapor. From Earth-based radar and spacecraft images of the crater edge, Shackleton appears to be relatively intact; much like a young crater that has not been significantly eroded from subsequent impacts. This may mean that the inner sides are relatively steep, which may make traversing the sides relatively difficult for a robotic vehicle. In addition, it

2808-473: The seasonal behaviour of the Sun, but with a period of 27.2 days instead of 365 days. Note that a point on the Moon can actually be visible when it is about 34 arc minutes below the horizon, due to atmospheric refraction . Because of the inclination of the Moon's orbit with respect to the Earth's equator, the Moon is above the horizon at the North and South Pole for almost two weeks every month, even though

2886-403: The Earth and accelerates the Moon, but because the ocean dissipates so much tidal energy, the present ocean tides have an order of magnitude greater effect than the solid Earth tides. Because of the tidal torque, caused by the ellipsoids, some of Earth's angular (or rotational) momentum is gradually being transferred to the rotation of the Earth–Moon pair around their mutual centre of mass, called

2964-411: The Moon across and the maximum Earth tide. As the Earth rotates faster than the Moon travels around its orbit, this small angle produces a gravitational torque which slows the Earth and accelerates the Moon in its orbit. In the case of the ocean tides, the speed of tidal waves in the ocean is far slower than the speed of the Moon's tidal forcing. As a result, the ocean is never in near equilibrium with

3042-413: The Moon is not perpendicular to its orbital plane, so the lunar equator is not in the plane of its orbit, but is inclined to it by a constant value of 6.688° (this is the obliquity ). As was discovered by Jacques Cassini in 1722, the rotational axis of the Moon precesses with the same rate as its orbital plane, but is 180° out of phase (see Cassini's Laws ) . Therefore, the angle between the ecliptic and

3120-472: The Moon would be in a mutual spin–orbit resonance or tidal locking , in which the Moon will orbit Earth in about 47 days (currently 27 days), and both the Moon and Earth would rotate around their axes in the same time, always facing each other with the same side. This has already happened to the Moon—the same side always faces Earth—and is also slowly happening to the Earth. However, the slowdown of Earth's rotation

3198-410: The Moon's apparent size changes as it moves toward and away from an observer on Earth. An event called a " supermoon " occurs when the full Moon is closest to Earth (perigee). The largest possible apparent diameter of the Moon is the same 12% larger (as perigee versus apogee distances) than the smallest; the apparent area is 25% more and so is the amount of light it reflects toward Earth. The variance in

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3276-420: The Moon's orbital distance corresponds with changes in its tangential and angular speeds, per Kepler's second law . The mean angular movement relative to an imaginary observer at the Earth–Moon barycentre is 13.176 ° per day to the east ( J2000.0 epoch). The Moon's elongation is its angular distance east of the Sun at any time. At new moon, it is zero and the Moon is said to be in conjunction . At full moon,

3354-699: The South Pole. The Moon's light is used by zooplankton in the Arctic when the Sun is below the horizon for months and must have been helpful to the animals that lived in Arctic and Antarctic regions when the climate was warmer. About 1000 BC , the Babylonians were the first human civilization known to have kept a consistent record of lunar observations. Clay tablets from that period, which have been found in Iraq, are inscribed with cuneiform writing recording

3432-599: The Sun is below the horizon for six months at a time. The period from moonrise to moonrise at the poles is a tropical month , about 27.3 days, quite close to the sidereal period. When the Sun is the furthest below the horizon ( winter solstice ), the Moon will be full when it is at its highest point. When the Moon is in Gemini it will be above the horizon at the North Pole, and when it is in Sagittarius it will be up at

3510-431: The Sun, Earth, and Moon align in three dimensions. In effect, this means that the " tropical year " on the Moon is only 347 days long. This is called the draconic year or eclipse year. The "seasons" on the Moon fit into this period. For about half of this draconic year, the Sun is north of the lunar equator (but at most 1.543°), and for the other half, it is south of the lunar equator. The effect of these seasons, however,

3588-408: The Sun, and the Moon. The anomalistic month is the time between perigees and is about 27.55 days. The Earth–Moon separation determines the strength of the lunar tide raising force. The draconic month is the time from ascending node to ascending node. The time between two successive passes of the same ecliptic longitude is called the tropical month . The latter periods are slightly different from

3666-399: The Sun. Consequently, Earth's centre veers inside and outside the solar orbital path during each synodic month as the Moon moves in its orbit around the common centre of gravity. The Sun's gravitational effect on the Moon is more than twice that of Earth's on the Moon; consequently, the Moon's trajectory is always convex (as seen when looking Sunward at the entire Sun–Earth–Moon system from

3744-426: The angular velocity. If the thumb of the right hand points to the north celestial pole, its fingers curl in the direction that the Moon orbits Earth, Earth orbits the Sun, and the Moon and Earth rotate on their own axes. In representations of the Solar System , it is common to draw the trajectory of Earth from the point of view of the Sun, and the trajectory of the Moon from the point of view of Earth. This could give

3822-444: The barycentre. See tidal acceleration for a more detailed description. This slightly greater orbital angular momentum causes the Earth–Moon distance to increase at approximately 38 millimetres per year. Conservation of angular momentum means that Earth's axial rotation is gradually slowing, and because of this its day lengthens by approximately 24 microseconds every year (excluding glacial rebound ). Both figures are valid only for

3900-585: The benefits previously identified by lunar researchers Burton Sharpe and David Schrunk. The equipment would include both a 2 metres (6 ft 7 in) radio telescope as well as an optical telescope . This is the specific mission design of the mission first announced publicly the previous year, in collaboration with the International Lunar Observatory Association (ILOA). As of February 2024 no such mission has yet flown. The Nova-C lunar lander Odysseus , used for

3978-400: The crater floor. Under these conditions, the estimated rate of loss from any ice in the interior would be 10 to 10  m/s. Any water vapor that arrives here following a cometary impact on the Moon would lie permanently frozen on or below the surface. However, the surface albedo of the crater floor matches the lunar far-side, suggesting that there is no exposed surface ice. This crater

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4056-473: The crater, which may indicate the presence of water ice. The crater is named after Antarctic explorer Ernest Shackleton . The rotational axis of the Moon passes through Shackleton, near the rim. The crater is 21 km (13 miles) in diameter and 4.2 km (2.6 miles) deep. From the Earth, it is viewed edge-on in a region of rough, cratered terrain. It is located within the South Pole–Aitken basin on

4134-639: The current configuration of the continents. Tidal rhythmites from 620 million years ago show that, over hundreds of millions of years, the Moon receded at an average rate of 22 mm (0.87 in) per year (2200 km or 0.56% or the Earth-moon distance per hundred million years) and the day lengthened at an average rate of 12 microseconds per year (or 20 minutes per hundred million years), both about half of their current values. The present high rate may be due to near resonance between natural ocean frequencies and tidal frequencies. Another explanation

4212-401: The direction of the pole of rotation of the Moon in space: but these are very small. When viewed from the north celestial pole (that is, from the approximate direction of the star Polaris ) the Moon orbits Earth anticlockwise and Earth orbits the Sun anticlockwise, and the Moon and Earth rotate on their own axes anticlockwise. The right-hand rule can be used to indicate the direction of

4290-542: The early nineteenth century. The shadowed portion of the crater was imaged with the Terrain Camera of the Japanese SELENE spacecraft using the illumination of sunlight reflected off the rim. The interior of the crater consists of a symmetrical 30° slope that leads down to a 6.6 km (4.1 miles) diameter floor. The handful of craters along the interior span no more than a few hundred meters. The bottom

4368-418: The ecliptic with a period of 18.6 years or 19.3549° per year. When viewed from the celestial north, the nodes move clockwise around Earth, opposite to Earth's own spin and its revolution around the Sun. An eclipse of the Moon or Sun can occur when the nodes align with the Sun, roughly every 173.3 days. Lunar orbit inclination also determines eclipses; shadows cross when nodes coincide with full and new moon when

4446-410: The elongation is 180° and it is said to be in opposition . In both cases, the Moon is in syzygy , that is, the Sun, Moon and Earth are nearly aligned. When elongation is either 90° or 270°, the Moon is said to be in quadrature . The orientation of the orbit is not fixed in space but rotates over time. This orbital precession is called apsidal precession and is the rotation of the Moon's orbit within

4524-419: The equator and the north pole is visible. This is called libration in latitude . The nodes are points at which the Moon's orbit crosses the ecliptic. The Moon crosses the same node every 27.2122 days, an interval called the draconic month or draconitic month . The line of nodes, the intersection between the two respective planes, has a retrograde motion : for an observer on Earth, it rotates westward along

4602-420: The equator to produce a present inclination of 5° to the ecliptic. It is thought that originally the inclination to the equator was near zero, but it could have been increased to 10° through the influence of planetesimals passing near the Moon while falling to the Earth. If this had not happened, the Moon would now lie much closer to the ecliptic and eclipses would be much more frequent. The rotational axis of

4680-488: The first scientific study in human history. However, the Babylonians seem to have lacked any geometric or physical interpretation of their data, and they could not predict future lunar eclipses (though "warnings" were issued before likely eclipse times). Ancient Greek astronomers were the first to introduce and analyze mathematical models of the motion of objects in the sky. Ptolemy described lunar motion by using

4758-495: The images in her presentation show the Malapert Mountain area well. In the 1970s British science fiction series Space: 1999 , the location of Moonbase Alpha is Malapert Crater. The International Lunar Observatory (ILO-1) is a lunar-based optical telescope that will be launched after 2022, and will land on the Malapert Mountain ridge. Shackleton (crater) Shackleton is an impact crater that lies at

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4836-404: The impression that the Moon orbits Earth in such a way that sometimes it goes backwards when viewed from the Sun's perspective. However, because the orbital velocity of the Moon around Earth (1 km/s) is small compared to the orbital velocity of Earth about the Sun (30 km/s), this never happens. There are no rearward loops in the Moon's solar orbit. Considering the Earth–Moon system as

4914-411: The inclination is at its maximum of 28°36', the centre of the Moon's disk will be above the horizon every day only from latitudes less than 60°27' (90° − 28°36' – 57' parallax) north or south. At higher latitudes , there will be a period of at least one day each month when the Moon does not rise, but there will also be a period of at least one day each month when the Moon does not set. This is similar to

4992-481: The inner walls of Shackleton are similar in reflective characteristics to those of some sunlit craters. In particular, the surroundings appear to contain a significant number of blocks in its ejecta blanket, suggesting that its radar properties are a result of surface roughness, and not ice deposits, as was previously suggested from a radar experiment involving the Clementine mission . This interpretation, however,

5070-403: The lunar equator is always 1.543°, even though the rotational axis of the Moon is not fixed with respect to the stars. It also means that when the Moon is farthest north of the ecliptic, the centre of the part seen from Earth is about 6.7° south of the lunar equator and the south pole is visible, whereas when the Moon is farthest south of the ecliptic the centre of the visible part is 6.7° north of

5148-464: The normal to the plane of the ecliptic. This leads to a similar perspective effect in the north–south direction that is referred to as optical libration in latitude , which allows one to see almost 7° of latitude beyond the pole on the far side. Finally, because the Moon is only about 60 Earth radii away from Earth's centre of mass, an observer at the equator who observes the Moon throughout the night moves laterally by one Earth diameter. This gives rise to

5226-437: The orbital plane, i.e. the axes of the ellipse change direction. The lunar orbit's major axis – the longest diameter of the orbit, joining its nearest and farthest points, the perigee and apogee , respectively – makes one complete revolution every 8.85 Earth years, or 3,232.6054 days, as it rotates slowly in the same direction as the Moon itself (direct motion) – meaning precesses eastward by 360°. The Moon's apsidal precession

5304-412: The point in the sky where the equator of the Moon crosses the ecliptic. When the Sun reaches that point, the centre of the Sun rises at the lunar north pole and sets at the lunar south pole. Every 18.6 years, the angle between the Moon's orbit and Earth's equator reaches a maximum of 28°36′, the sum of Earth's equatorial tilt (23°27′) and the Moon's orbital inclination (5°09′) to the ecliptic . This

5382-444: The presence of water in the polar craters, the current evidence is far from definitive. There are doubts among scientists as to whether or not the hydrogen is in the form of ice, as well as to the concentration of this "ore" with depth below the surface. Resolution of this issue will require future missions to the Moon. The potential presence of water suggests that the crater floor could be "mined" for deposits of hydrogen in water form,

5460-426: The sidereal month. The average length of a calendar month (a twelfth of a year) is about 30.4 days. This is not a lunar period, though the calendar month is historically related to the visible lunar phase. The gravitational attraction that the Moon exerts on Earth is the cause of tides in both the ocean and the solid Earth; the Sun has a smaller tidal influence. The solid Earth responds quickly to any change in

5538-419: The sky having right ascension zero and declination zero). The nodes are moving west by about 19° per year. The Sun crosses a given node about 20 days earlier each year. When the inclination of the Moon's orbit to the Earth's equator is at its minimum of 18°20′, the centre of the Moon's disk will be above the horizon every day from latitudes less than 70°43' (90° − 18°20' – 57' parallax) north or south. When

5616-472: The south pole would provide energy for solar panels. Furthermore, the shadowed polar regions are believed to contain the frozen water necessary for human consumption and could also be harvested for fuel manufacture. The crater is a major landing site candidate for the Artemis program and could be explored by a crew starting in 2026 with a possible first lunar outpost in 2028. Shackleton plays prominently in

5694-420: The tidal forcing, the distortion taking the form of an ellipsoid with the high points roughly beneath the Moon and on the opposite side of Earth. This is a result of the high speed of seismic waves within the solid Earth. However the speed of seismic waves is not infinite and, together with the effect of energy loss within the Earth, this causes a slight delay between the passage of the maximum forcing due to

5772-462: The tidal forcing. Instead, the forcing generates the long ocean waves which propagate around the ocean basins until eventually losing their energy through turbulence, either in the deep ocean or on shallow continental shelves. Although the ocean's response is the more complex of the two, it is possible to split the ocean tides into a small ellipsoid term which affects the Moon plus a second term which has no effect. The ocean's ellipsoid term also slows

5850-481: The times and dates of moonrises and moonsets, the stars that the Moon passed close by, and the time differences between rising and setting of both the Sun and the Moon around the time of a full moon . Babylonian astronomy discovered the three main periods of the Moon's motion and used data analysis to build lunar calendars that extended well into the future. This use of detailed, systematic observations to make predictions based on experimental data may be classified as

5928-561: Was also the site of the first lunar base in Mass Effect . It was chosen as a location due to its hypothesised water ice deposits. Shackleton was the location for the site of the Chinese National Space Agency moonbase Guang Han Gong-1 in the fictional podcast series Transmissions from Colony One . Pusher (musician) , in his album published in late September 2023 named "King of the Moon", heavily references

6006-434: Was crashed into the nearby crater Shoemaker in the hope of detecting from Earth-based telescopes an impact-generated plume containing water vapor. The impact event did not produce any detectable water vapor, and this may be an indication that the hydrogen is not in the form of hydrated minerals , or that the impact site did not contain any ice. Alternatively, it is possible that the crash did not excavate deeply enough into

6084-553: Was named after Ernest Shackleton , an Anglo-Irish explorer of Antarctica from 1901 until his death in 1922. The name was officially adopted by the International Astronomical Union in 1994. Nearby craters of note include Shoemaker , Haworth , de Gerlache , Sverdrup , Slater , and Faustini . Somewhat farther away, on the eastern hemisphere of the lunar near side, are the larger craters Amundsen and Scott , named after two other early explorers of

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