2.) The Far Side The side of the Moon unseen from the Earth is called the far side. When selecting the Apollo 16 landing site, the highest priority was given to landing at a site in the lunar highlands, which occupy more than five times the surface area occupied by mare units. In addition, ∼45 impacts produced basins, ranging in diameter from Bailly at 300 km, through the South Pole-Aitken Basin at 2600 km, to the putative Procellarum Basin at 3500 km, the existence of which is still debated. The FeO content is significantly less than many of the surfaces of the Moon and other terrestrial planets. The Moon’s heavily cratered highlands are made of rocks more than 4 billion years old. Upcoming missions planned for launch in 2007–2008 by Japan (SELENE), India (Chandrayaan-1), and China (Chang'e) will each carry X-ray spectrometers to obtain further improved maps of the Moon's elementalcom position, at ∼20-to 50-km resolution from ∼100- to 200-km altitude polar orbits. Definition of moon in the Definitions.net dictionary. This illustrates the very high cratering prior to 3.8 billion years ago, but whether this represents the tail end of accretion or spike (cataclysm), as preferred here, in the bombardment history is unclear. Thus, X-ray fluorescence studies provide an excellent way to determine the elemental composition of the lunar surface by remote sensing, since at X-ray wavelengths the optical properties of the surface are dominated by its elemental abundances. However, the lunar highlands differ from the lunar lowlands mainly in their concentrations of the metal oxides. The highlands consist primarily of anorthosite. This is abnormally low compared to other terrestrial planets and the Moon. The Moon is farther away from Earth than most people realize. The Maria are lower in altitude than the Highlands, but there is no water on the Moon so they are not literally seas ( Recent evidence from the Clementine spacecraft suggests that there may be some water on the Moon, contrary to previous assumptions). Figure 3a shows a radio image at 3.6 cm, probing a depth of ∼70 cm. a thin, gray layer on the surface on the moon. ... Area 51, Starship, and Harvest Moon: September’s Words in the News. Previous research has found similar surface features in the Moon's highlands, but wrinkle ridges have never been seen in basins before now. The viewing geometry is superimposed on the latter image. We use cookies to help provide and enhance our service and tailor content and ads. A lot of. A microwave image of the full Moon reveals that the maria are ∼5 K warmer than the highlands. The site of the Apollo 11 Moon landing was the Mare Tranquillitatis, "Sea of Tranquility." The reaction CO + OH → CO2 + H frees up H, which eventually may lead to the formation of hydrogen peroxide (H2O2), a strong oxidizer. The observed O–K line photons correspond to a flux of 3.8 × 10−5 photons/s/cm2/arcmin2 (3.2 × 10−14 erg/s/cm2/arcmin2). New ideas being pursued include the creation of OH by electric fields in martian dust storms. On the Moon, surfaces are either densely covered by large craters (lunar highlands) or sparsely affected by large craters (maria) with no surfaces of intermediate crater densities. The dark features, called maria (Latin for seas), are impact basins that were filled with lava between 4.2 and 1.2 billion years ago. Anil Bhardwaj, Carey M. Lisse, in Encyclopedia of the Solar System (Second Edition), 2007. Regular photolysis of water in the martian atmosphere may be too slow, however. (a) The 3.6 cm thermal emission from Mercury observed with the VLA. The Moon. Only their fusion crust differentiates them from Apollo and Luna samples. On Venus, one probes the so-called mesosphere in these transitions, a region between the massive lower atmosphere (altitudes ≲70 km), in which the radiative time constant is much greater than a solar day, and the upper atmosphere (altitudes ≥120 km), which has a low heat capacity. The brightness scale in R assumes an average effective area of 100 cm2 for the ROSAT PSPC over the lunar spectrum. The observed albedo contrast was noticeable, but very slight, making remote elemental mapping difficult. The way in which light is reflected from the surface is very similar to that of the Moon. Thus the color difference. There is considerable uncertainty in estimating absolute ages this way because we do not know exactly what the cratering rate on Mars has been for the past few billion years. FIGURE 14. The volume of crust melted in a basin-forming event of this size is on the order of a 1 × 106 km3. About 85% of the Moon’s surface is covered by lunar highlands. Lunar highlands, on the other hand, also called terrae, are the light colored parts of the Moon. The Mg–K, Al–K, and Si–K lines each had roughly 10% as many counts and 3% as much flux as O–K line, but statistics were inadequate to draw any conclusions regarding differences in element abundance ratios between highlands and maria. The rates on the other terrestrial planets are likely to be within a factor of 2 or 3 of these rates. Earlier suggestions had the night side X-rays produced by bremsstrahlung of solar wind electrons of several hundred eV impacting the night side of the Moon on its evening (leading) hemisphere. With a radius of 1,079.6 miles (1,737.5 kilometers), the Moon is less than a third the width of Earth. On both planets, CO2 gas is photodissociated (molecules are broken up) by sunlight at high altitudes into carbon monoxide (CO) and oxygen (O). Mercury's peak (noon) surface temperature varies between 700 K for longitudes facing the Sun at perihelion (longitudes 0° and 180°) to 570 K 90° away. The two hot regions discussed previously are clearly visible. It seems probable that accretion of the Moon was essentially complete and that the Moon was at its present size by about 4450 million years ago, at the time of the crystallization of the feldspathic highland crust. Highlands definition, a mountainous region in N Scotland, N of the Grampians. These are likely caused by shadows on the surface resulting from local topography, such as craters. This may result from a difference in albedo (the maria are darker than the highlands), radio emissivity and/or the microwave opacity. Note the two so-called hot regions, discussed in the text. The moon's highlands are its old, mountainous regions. It would take thousands of years for the water-saturated atmosphere to rain out and reform the oceans. There are only two types of regions on the Moon's surface. They are basically round, although some overlap. However, we see instead large negative (blue) temperatures near the poles and along the morning side of the terminator. The green dotted curve is the detector background. The Moon’s basaltic rocks are fine-grained composed mainly by iron, magnesium and titanium. It has a rocky silicate composition and is of planetary mass but has no significant atmosphere , hydrosphere or magnetic field . The, proportional counters was low, important results were obtained, such as the enhancement of Al/Si in the, Encyclopedia of the Solar System (Third Edition). FIGURE 4. A radio spectrum of Venus. Venus and Mars have atmospheres which consist of over 95% carbon dioxide gas (CO2). Other arguments in favor of the cataclysm include the scarcity of impact melts older than 4 billion years and the lead isotope data, which indicate a major resetting of the lead ages at 3.86 billion years. The FeO content appears to be between 1 and 3%. FIGURE 15. What does moon trefoil mean? Since the iron content of lavas is thought to be representative of their mantle source regions, it is estimated that Mercury's mantle has about the same FeO content (<6 weight percent) as the crust, indicating Mercury is highly reduced with most of the iron in the core. ScienceDirect ® is a registered trademark of Elsevier B.V. ScienceDirect ® is a registered trademark of Elsevier B.V. URL: https://www.sciencedirect.com/science/article/pii/B9780120885893500165, URL: https://www.sciencedirect.com/science/article/pii/B9780120885893500475, URL: https://www.sciencedirect.com/science/article/pii/B9780120885893500177, URL: https://www.sciencedirect.com/science/article/pii/B9780120885893500207, URL: https://www.sciencedirect.com/science/article/pii/B9780120885893500104, URL: https://www.sciencedirect.com/science/article/pii/B9780120885893500396, URL: https://www.sciencedirect.com/science/article/pii/B9780120885893500426, Encyclopedia of the Solar System (Second Edition), (Updated from the Basaltic Volcanism Study Project, 1981. Like on all planetary crusts and the dirt under your feet here on Earth, lunar material consists predominantly of silicate minerals, i.e., silicon and oxygen molecularly bonded to various metal atoms. Mapping Lunar Highlands . They are the light and dark areas. GTR values under the equal masses approach for compensation entirely with variations in thickness of the crust are too high, especially for the farside highlands… From the highlands to the plains, the European Space Agency’s SMART-1 probe is giving scientists an up-close view of the dark and light areas on the Moon. Introduction: The Fission Theory of the formation of the Moon was proposed much earlier than the Impact Theory and was proposed originally by George Darwin (son of Charles Darwin) in 1879 [27]. Another word for highlands. I’m sure a lot of people would agree that we live in strange times. The lunar mountain ranges, with heights up to 25,000 ft (7,800 m), are comparable to the highest mountains on earth but in general are not very steep. ... a thin, gray layer on the surface on the moon. These differences in albedo suggest that there are systematic differences in the surface composition between the two bodies. Accordingly, surfaces that formed prior to 3.8 billion years ago are heavily cratered, and those that formed afterward are much less cratered. This is a surprisingly narrow range and indicates a rapid increase in the cratering flux just before 3.8 billion years. Both are essential parameters in modeling radio observations of the Moon. Define highland. Most highland samples have ages in the range 3.8–4.3 billion years. The large multiring basins define the major topographic features of the Moon. On Earth, in an area the size of the United States, a crater larger than 10 km across is expected to form every 10–20 million years and one larger than 100 km across, every billion years. Maria are the largest topographic features on the Moon and can be seen from Earth with the unaided eye. Therefore, contrary to expectations, the spectra in Fig. Definition. The elevation of lunar highlands is 2–3 km higher than maria, and the areas tend to be larger than maria. Radio images of Mercury show a brightness variation across the disk, which displays the history of solar insolation. Know the hours of the rising and setting of the moon in Highlands. These have diffuse boundaries that may be associated with fractures (Fig. Figure 15 shows a reconstruction of the lunar crater production rate with time. Lunar meteorites total ∼11.2 kg, much less than the 382 kg of Apollo and Luna material, but they provide very important lunar information. Highlands vs. Lowlands Geologies. The radiometric ages of the ejecta blankets from the large collisions tend to cluster around 3.9 billion years, with the dates for the Imbrium collision being 3.85 billion years and that for Nectaris, 3.90 or 3.92 billion years. ’ m sure a lot of people would agree that we only see one side by a ilmenite... Photons/S/Cm2/Arcmin2 ( 3.2 × 10−14 erg/s/cm2/arcmin2 ) the morning side of the Moon 's.! 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