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Amazonian (Mars)
The Amazonian is a geologic system and time period on the planet Mars characterized by low rates of meteorite and asteroid impacts and by cold, hyperarid conditions broadly similar to those on Mars today.Carr, M.H. (2006), The Surface of Mars. Cambridge Planetary Science Series, Cambridge University Press. The transition from the preceding Hesperian period is somewhat poorly defined. The Amazonian is thought to have begun around 3 billion years ago, although error bars on this date are extremely large (~500 million years). The period is sometimes subdivided into the Early, Middle, and Late Amazonian. The Amazonian continues to the present day. The Amazonian period has been dominated by impact crater formation and Aeolian processes with ongoing isolated volcanism occurring in the Tharsis region and Cerberus Fossae, including signs of activity as recently as a tens of thousands of years ago in the latter and within the past few million years on Olympus Mons, implying ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hesperian
The Hesperian is a system (stratigraphy), geologic system and geologic timescale, time period on the planet Mars characterized by widespread Volcanology of Mars, volcanic activity and catastrophic flooding that carved immense outflow channels across the surface. The Hesperian is an intermediate and transitional period of Martian history. During the Hesperian, Mars changed from the wetter and perhaps warmer world of the Noachian (Mars), Noachian to the dry, cold, and dusty planet seen today. The absolute age of the Hesperian Period is uncertain. The beginning of the period followed the end of the Late Heavy Bombardment and probably corresponds to the start of the lunar Late Imbrian period, around 3700 million years ago (Myr, Mya). The end of the Hesperian Period is much more uncertain and could range anywhere from 3200 to 2000 Mya, with 3000 Mya being frequently cited. The Hesperian Period is roughly coincident with the Earth's early Archean Eon. With the decline of heavy impacts a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amazonian (Mars)
The Amazonian is a geologic system and time period on the planet Mars characterized by low rates of meteorite and asteroid impacts and by cold, hyperarid conditions broadly similar to those on Mars today.Carr, M.H. (2006), The Surface of Mars. Cambridge Planetary Science Series, Cambridge University Press. The transition from the preceding Hesperian period is somewhat poorly defined. The Amazonian is thought to have begun around 3 billion years ago, although error bars on this date are extremely large (~500 million years). The period is sometimes subdivided into the Early, Middle, and Late Amazonian. The Amazonian continues to the present day. The Amazonian period has been dominated by impact crater formation and Aeolian processes with ongoing isolated volcanism occurring in the Tharsis region and Cerberus Fossae, including signs of activity as recently as a tens of thousands of years ago in the latter and within the past few million years on Olympus Mons, implying ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mars Orbital Laser Altimeter
image:PIA02040 Martian hemispheres by MOLA.jpg, 260px, MOLA topographic images of the two hemispheres of Mars. This image appeared on the cover of ''Science'' magazine in May 1999. The Mars Orbiter Laser Altimeter (MOLA) was one of five instruments on the ''Mars Global Surveyor'' (MGS) spacecraft, which operated in Mars orbit from September 1997 to November 2006. However, the MOLA instrument transmitted altimetry data only until June 2001. The MOLA instrument transmitted infrared laser pulses towards Mars at a rate of 10 times per second and measured the time of flight to determine the range (distance) of the MGS spacecraft to the Martian surface. The range measurements resulted in precise topography, topographic maps of Mars. The precision maps are applicable to studies in geophysics, geology and atmospheric circulation. MOLA also functioned as a passive radiometer and measured the radiance of the surface of Mars at 1064 nanometers. Planetary laser altimetry A laser altimeter is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olympus Mons
Olympus Mons (; ) is a large shield volcano on Mars. It is over high as measured by the Mars Orbiter Laser Altimeter (MOLA), about 2.5 times the elevation of Mount Everest above sea level. It is Mars's tallest volcano, its tallest planetary mountain, and is approximately tied with Rheasilvia on Vesta as the tallest mountain currently discovered in the Solar System. It is associated with the volcanic region of Tharsis Montes. It last erupted 25 million years ago. Olympus Mons is the youngest of the large volcanoes on Mars, having formed during the Martian Hesperian Period with eruptions continuing well into the Amazonian Period. It has been known to astronomers since the late 19th century as the albedo feature Nix Olympica (Latin for "Olympic Snow"), and its mountainous nature was suspected well before space probes confirmed it as a mountain. Two impact craters on Olympus Mons have been assigned provisional names by the International Astronomical Union: the Karzok crater a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Insolation
Solar irradiance is the power per unit area ( surface power density) received from the Sun in the form of electromagnetic radiation in the wavelength range of the measuring instrument. Solar irradiance is measured in watts per square metre (W/m2) in SI units. Solar irradiance is often integrated over a given time period in order to report the radiant energy emitted into the surrounding environment (joule per square metre, J/m2) during that time period. This integrated solar irradiance is called solar irradiation, solar radiation, solar exposure, solar insolation, or insolation. Irradiance may be measured in space or at the Earth's surface after atmospheric absorption and scattering. Irradiance in space is a function of distance from the Sun, the solar cycle, and cross-cycle changes.Michael Boxwell, ''Solar Electricity Handbook: A Simple, Practical Guide to Solar Energy'' (2012), pp. 41–42. Irradiance on the Earth's surface additionally depends on the tilt of the measur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chaos Theory
Chaos theory is an interdisciplinary area of Scientific method, scientific study and branch of mathematics. It focuses on underlying patterns and Deterministic system, deterministic Scientific law, laws of dynamical systems that are highly sensitive to initial conditions. These were once thought to have completely random states of disorder and irregularities. Chaos theory states that within the apparent randomness of chaotic complex systems, there are underlying patterns, interconnection, constant feedback loops, repetition, self-similarity, fractals and self-organization. The butterfly effect, an underlying principle of chaos, describes how a small change in one state of a deterministic nonlinear system can result in large differences in a later state (meaning there is sensitive dependence on initial conditions). A metaphor for this behavior is that a butterfly flapping its wings in Brazil can cause or prevent a tornado in Texas. Text was copied from this source, which is avai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jupiter
Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a Jupiter mass, mass more than 2.5 times that of all the other planets in the Solar System combined and slightly less than one-thousandth the mass of the Sun. Its diameter is 11 times that of Earth and a tenth that of the Sun. Jupiter orbits the Sun at a distance of , with an orbital period of . It is the List of brightest natural objects in the sky, third-brightest natural object in the Earth's night sky, after the Moon and Venus, and has been observed since prehistoric times. Its name derives from that of Jupiter (god), Jupiter, the chief deity of ancient Roman religion. Jupiter was the first of the Sun's planets to form, and its inward migration during the primordial phase of the Solar System affected much of the formation history of the other planets. Jupiter's atmosphere consists of 76% hydrogen and 24% helium by mass, with a denser ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crater Counting
Crater counting is a method for estimating the age of a planet's surface based upon the assumptions that when a piece of planetary surface is new, then it has no impact craters; impact craters accumulate after that at a rate that is assumed known. Consequently, counting how many craters of various sizes there are in a given area allows determining how long they have accumulated and, consequently, how long ago the surface has formed. The method has been calibrated using the ages obtained by radiometric dating of samples returned from the Moon by the Luna programme, Luna and Apollo program, Apollo missions. It has been used to estimate the age of areas on Mars and other planets that were covered by lava flows, on the Moon of areas covered by giant lunar mare, mares, and how long ago areas on the Moons of Jupiter, icy moons of Jupiter and Moons of Saturn, Saturn flooded with new ice. Crater counting and secondary craters The crater counting method requires the presence of independent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Law Of Superposition
The law of superposition is an axiom that forms one of the bases of the sciences of geology, archaeology, and other fields pertaining to geological stratigraphy. In its plainest form, it states that in undeformed stratigraphic sequences, the oldest strata will lie at the bottom of the sequence, while newer material stacks upon the surface to form new deposits over time. This is paramount to stratigraphic dating, which requires a set of assumptions, including that the law of superposition holds true and that an object cannot be older than the materials of which it is composed. To illustrate the practical applications of superposition in scientific inquiry, sedimentary rock that has not been deformed by more than 90° will exhibit the oldest layers on the bottom, thus enabling paleontologists and paleobotanists to identify the relative ages of any fossils found within the strata, with the remains of the most archaic lifeforms confined to the lowest. These findings can inform t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lava Flow And Crater Ejecta
Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a Natural satellite, moon onto its surface. Lava may be erupted at a volcano or through a Fissure vent, fracture in the Crust (geology), crust, on land or underwater, usually at temperatures from . The volcanic rock resulting from subsequent cooling is often also called ''lava''. A lava flow is an outpouring of lava during an effusive eruption. (An explosive eruption, by contrast, produces a mixture of volcanic ash and other fragments called tephra, not lava flows.) The viscosity of most lava is about that of ketchup, roughly 10,000 to 100,000 times that of water. Even so, lava can flow great distances before cooling causes it to solidify, because lava exposed to air quickly develops a solid crust that insulates the remaining liquid lava, helping to keep it hot and inviscid enough to continue flowing. Etymology The word ''lava'' comes from Ital ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geological History Of Mars
The geological history of Mars follows the physical evolution of Mars as substantiated by observations, indirect and direct measurements, and various inference techniques. Methods dating back to 17th-century techniques developed by Nicholas Steno, including the so-called law of superposition and stratigraphy, used to estimate the geological histories of Earth and the Moon, are being actively applied to the data available from several Martian observational and measurement resources. These include landers, orbiting platforms, Earth-based observations, and Martian meteorites. Observations of the surfaces of many Solar System bodies reveal important clues about their evolution. For example, a lava flow that spreads out and fills a large impact crater is likely to be younger than the crater. On the other hand, a small crater on top of the same lava flow is likely to be younger than both the lava and the larger crater since it can be surmised to have been the product of a later, unobs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pre-Noachian
The Pre-Noachian period is a System (stratigraphy), geological system and early Geologic time scale, time period on Mars marked by intense meteoroid and asteroid Impact event, impacts, volcanic activity, volcanic and Tectonics of Mars, tectonic activity, and the potential presence of surface water, surface or subsurface water. The era holds significant importance in Geological history of Mars, Mars' history as it witnessed the planet's formation and the shaping of its geological features. However, understanding the Pre-Noachian period remains elusive, as it is the least comprehended among Mars' four geological epochs. Much of the evidence from this period has been obscured by erosion and Deposition (geology), deposition processes. During the Pre-Noachian period, the northern hemisphere of Mars developed lowlands, which may have served as reservoirs for Water on Mars, ancient Martian water during subsequent epochs. These lowlands likely formed through lava erosion caused by extensi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
