"solar wind around itself called the magnetosphere, which the wind cannot penetrate. The magnetosphere can be much larger than the planet itself. In contrast, non-magnetized planets have only small magnetospheres induced by interaction of the ionosphere with the solar wind, which cannot effectively protect the planet. Of the eight planets in the Solar System, only Venus and Mars lack such a magnetic field. In addition, the moon of Jupiter Ganymede also has one. Of the magnetized planets the magnetic field of Mercury is the weakest, and is barely able to deflect the solar wind. Ganymede's magnetic field is several times"
"Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System after Mercury. In English, Mars carries a name of the Roman god of war, and is often referred to as the ""Red Planet"" because the reddish iron oxide prevalent on its surface gives it a reddish appearance that is distinctive among the astronomical bodies visible to the naked eye. Mars is a terrestrial planet with a thin atmosphere, having surface features reminiscent both of the impact craters of the Moon and the valleys, deserts, and polar ice caps of Earth. The rotational period"
"by a Martian orb. This was in significant contrast with Ursus's geoheliocentric model in which the orbits of Mercury and Venus intersect the Martian orbit but the Solar orbit does not, and also with the Tychonic model in which the Martian orbit also intersects the Solar orbit in addition to those of Mercury and Venus, and whereby both these models rule out solid celestial orbs that cannot interpenetrate, if not excluding interpenetrating fluid orbs. However, Wittich's Capellan model of the Martian orbit contradicted Copernicus's model in which Mars at opposition is nearer to the Earth than the Sun is, whereby"
"put forward as the most likely causes. In March 2015, scientists stated that evidence exists for an ancient Martian ocean, likely in the planet's northern hemisphere and about the size of Earth's Arctic Ocean, or approximately 19% of the Martian surface. This finding was derived from the ratio of water and deuterium in the modern Martian atmosphere compared to the ratio found on Earth. Eight times as much deuterium was found at Mars than exists on Earth, suggesting that ancient Mars had significantly higher levels of water. Results from the ""Curiosity"" rover had previously found a high ratio of deuterium"
"be abandoned, and a vogue for accurate, realist depictions of human colonies on Mars developed, the best known of which may be Kim Stanley Robinson's ""Mars"" trilogy. Pseudo-scientific speculations about the Face on Mars and other enigmatic landmarks spotted by space probes have meant that ancient civilizations continue to be a popular theme in science fiction, especially in film. Images Videos Cartographic resources Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System after Mercury. In English, Mars carries a name of the Roman god of war, and is often referred to as"
"Romanian, ""marţi"", in Spanish, ""martes"", in French, ""mardi"" and in Italian ""martedì""). The English ""Tuesday"" is a modernised form of ""Tyr's Day"", Tyr being the Germanic analogue to Mars. Dante Alighieri associated Mars with the liberal art of arithmetic. In Chinese astrology, Mars is ruled by the element fire, which is passionate, energetic and adventurous. In Indian astrology, Mars is called Mangala and represents energy, confidence and ego. Jupiter () is the ruling planet of Sagittarius and it is exalted in Cancer. In classical Roman mythology, Jupiter is the ruler of the gods and their guardian and protector, and his"
"tilts of the two planets' rotational axes. The lengths of the Martian seasons are about twice those of Earth's because Mars's greater distance from the Sun leads to the Martian year being about two Earth years long. Martian surface temperatures vary from lows of about at the winter polar caps to highs of up to in equatorial summer. The wide range in temperatures is due to the thin atmosphere which cannot store much solar heat, the low atmospheric pressure, and the low thermal inertia of Martian soil. The planet is 1.52 times as far from the Sun as Earth, resulting"
"gave his name to the third month in the Roman calendar, ""Martius"", from which English ""March"" derives. In the most ancient Roman calendar, ""Martius"" was the first month. The planet Mars was named for him, and in some allegorical and philosophical writings, the planet and the god are endowed with shared characteristics. In many languages, Tuesday is named for the planet Mars or the god of war: In Latin, ""martis dies"" (""Mars's Day""), survived in Romance languages as ""martes"" (Spanish), ""mardi"" (French), ""martedi"" (Italian), ""marţi"" (Romanian), and ""dimarts"" (Catalan). In Irish (Gaelic), the day is ""An Mháirt"", while in Albanian"
"Solar System, and include all non-Earth soils in a new World Reference Base for Soil Resources Reference Group or USDA soil taxonomy Order, which might be tentatively called Astrosols. On October 17, 2012 (Curiosity rover at ""Rocknest""), the first X-ray diffraction analysis of Martian soil was performed. The results revealed the presence of several minerals, including feldspar, pyroxenes and olivine, and suggested that the Martian soil in the sample was similar to the ""weathered basaltic soils"" of Hawaiian volcanoes. Hawaiian volcanic ash has been used as Martian regolith simulant by researchers since 1998. In December 2012, scientists working on the"
"Uranus Uranus (from the Latin name ""Ūranus"" for the Greek god Οὐρανός) is the seventh planet from the Sun. It has the third-largest planetary radius and fourth-largest planetary mass in the Solar System. Uranus is similar in composition to Neptune, and both have bulk chemical compositions which differ from that of the larger gas giants Jupiter and Saturn. For this reason, scientists often classify Uranus and Neptune as ""ice giants"" to distinguish them from the gas giants. Uranus' atmosphere is similar to Jupiter's and Saturn's in its primary composition of hydrogen and helium, but it contains more ""ices"" such as"
"show evidence of Methane and Acetylene but no Ammonia or Carbon Dioxide. There is currently no explanation why this planet shows strong methane absorption, but the other 3 planets in this system do not, despite all 4 planets having similar atmospheric temperatures. HR 8799 e </math></ref> HR 8799 e is a large exoplanet, orbiting the star HR 8799, which lies 129 lightyears from Earth. This gas giant is between 5 and 10 times the mass of Jupiter, the largest planet in the Solar System. Due to their young age and high temperature all four discovered planets in the HR 8799"
"Areostationary orbit An areostationary orbit or areosynchronous equatorial orbit (abbreviated AEO) is a circular areo­synchronous orbit in the Martian equatorial plane about above the surface, any point on which revolves about Mars in the same direction and with the same period as the Martian surface. Areo­stationary orbit is a concept similar to Earth's geo­stationary orbit. The prefix ""areo-"" derives from Ares, the ancient Greek god of war and counterpart to the Roman god Mars, with whom the planet was identified. The modern Greek word for Mars is ""Άρης"" (Áris). To date, no artificial satellites have been placed in this orbit,"
"has a semi-major axis of 23,463 km. The close proximity to Phobos in particular (the larger of the two moons) will cause unwanted orbital resonance effects that will gradually shift the orbit of areostationary satellites. Areostationary orbit An areostationary orbit or areosynchronous equatorial orbit (abbreviated AEO) is a circular areo­synchronous orbit in the Martian equatorial plane about above the surface, any point on which revolves about Mars in the same direction and with the same period as the Martian surface. Areo­stationary orbit is a concept similar to Earth's geo­stationary orbit. The prefix ""areo-"" derives from Ares, the ancient Greek god"
"researchers using the OMEGA instrument on the Mars Express spacecraft proposed a new Martian era called the Phyllocian, corresponding to the Pre-Noachian/Early Noachian in which surface water and aqueous weathering was common. Two subsequent eras, the Theiikian and Siderikian, were also proposed. The Phyllocian era correlates with the age of early valley network formation on Mars. It is thought that deposits from this era are the best candidates in which to search for evidence of past life on the planet. Noachian The Noachian is a geologic system and early time period on the planet Mars characterized by high rates of"
"from John Keats's ""On First Looking Into Chapman's Homer"", are a reference to Herschel's discovery of Uranus. Many references to Uranus in English language popular culture and news involve humour about one pronunciation of its name resembling that of the phrase ""your anus"". Uranus Uranus (from the Latin name ""Ūranus"" for the Greek god Οὐρανός) is the seventh planet from the Sun. It has the third-largest planetary radius and fourth-largest planetary mass in the Solar System. Uranus is similar in composition to Neptune, and both have bulk chemical compositions which differ from that of the larger gas giants Jupiter and"
"Center (DLR) and a study team with representatives of the scientific community and the space industry. The mission would explore the origin and the evolution of the two Martian moons, and would also contribute to the general questions of planetary formation and the workings of the Solar System. The origin of the Martian moons is controversial. Phobos and Deimos both have much in common with carbonaceous C-type asteroids, with spectra, albedo, and density very similar to those of C- or D-type asteroids. Based on their similarity, one hypothesis is that both moons may be captured main-belt asteroids. Another hypothesis is"
"orbit"" (abbreviated ""AEO"") is a circular areo­synchronous orbit in the Martian equatorial plane about above the surface, any point on which revolves about Mars in the same direction and with the same period as the Martian surface. Areo­stationary orbit is a concept similar to Earth's geo­stationary orbit. The prefix ""areo-"" derives from Ares, the ancient Greek god of war and counterpart to the Roman god Mars, with whom the planet was identified. The modern Greek word for Mars is (). Stationary orbit In celestial mechanics, the term stationary orbit refers to an orbit around a planet or moon where the"
"moon Triton to be investigated around 2029. The proposed ""New Horizons 2"" mission (which was later scrapped) might also have done a close flyby of the Neptunian system. Neptune Neptune is the eighth and farthest known planet from the Sun in the Solar System. In the Solar System, it is the fourth-largest planet by diameter, the third-most-massive planet, and the densest giant planet. Neptune is 17 times the mass of Earth and is slightly more massive than its near-twin Uranus, which is 15 times the mass of Earth and slightly larger than Neptune. Neptune orbits the Sun once every 164.8"
"then much of the bedrock in the Martian highlands is pre-Noachian in age, dating back to over 4100 million years ago. The Noachian System is subdivided into three chronostratigraphic series: Lower Noachian, Middle Noachian, and Upper Noachian. The series are based on ""referents"" or locations on the planet where surface units indicate a distinctive geological episode, recognizable in time by cratering age and stratigraphic position. For example, the referent for the Upper Noachian is an area of smooth intercrater plains east of the Argyre basin. The plains overlie (are younger than) the more rugged cratered terrain of the Middle Noachian"
"Ocean. This finding was derived from the ratio of water and deuterium in the modern Martian atmosphere compared to the ratio found on Earth and derived from telescopic observations. Eight times as much deuterium was inferred at the polar deposits of Mars than exists on Earth (VSMOW), suggesting that ancient Mars had significantly higher levels of water. The representative atmospheric value obtained from the maps (7 VSMOW) is not affected by climatological effects as those measured by localized rovers, although the telescopic measurements are within range to the enrichment measured by the ""Curiosity"" rover in Gale Crater of 5-7 VSMOW."
"of Earth's orbit, making it the first planet that does not set along with the Sun. Mars has two permanent polar ice caps. During a pole's winter, it lies in continuous darkness, chilling the surface and causing the deposition of 25–30% of the atmosphere into slabs of CO ice (dry ice). Astrologically speaking, Mars is associated with confidence and self-assertion, aggression, sexuality, energy, strength, ambition and impulsiveness. Mars governs sports, competitions and physical activities in general. The 1st-century poet Manilius, described the planet as ardent and as the lesser malefic. In medicine, Mars presides over the genitals, the muscular system,"
"Hesperian The Hesperian is a geologic system and time period on the planet Mars characterized by widespread 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 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"
"in just 43% of the amount of sunlight. If Mars had an Earth-like orbit, its seasons would be similar to Earth's because its axial tilt is similar to Earth's. The comparatively large eccentricity of the Martian orbit has a significant effect. Mars is near perihelion when it is summer in the southern hemisphere and winter in the north, and near aphelion when it is winter in the southern hemisphere and summer in the north. As a result, the seasons in the southern hemisphere are more extreme and the seasons in the northern are milder than would otherwise be the case."
"underlying surface appears dark. Much of the Martian surface is covered with dust. Dust storms are frequent, especially when the spring season begins in the southern hemisphere. At that time, Mars is 40% closer to the sun. The orbit of Mars is much more elliptical then the Earth's. That is the difference between the farthest point from the sun and the closest point to the sun is very great for Mars, but only slight for the Earth. Also, every few years, the entire planet is engulfed in a global dust storm. When NASA's Mariner 9 craft arrived there, nothing could"
"era, perhaps with a more intense greenhouse effect, or a lower albedo, than at present. Current Martian surface temperatures vary from lows of about −87 °C (−125 °F) during polar winter to highs of up to −5 °C (23 °F) in summer. The wide range is due to the rarefied atmosphere, which cannot store much solar heat, and the low thermal inertia of the soil. Early in its history, a denser atmosphere may have permitted the formation of an ocean on Mars. The planet is thought to be located within the habitable zone of its parent star, a red dwarf,"
"by impact crater density, which is heavily dependent upon models of crater formation over time. Accordingly, the beginning and end dates for Martian periods are uncertain, especially for the Hesperian/Amazonian boundary, which may be in error by a factor of 2 or 3. The lower boundary of the Hesperian System is defined as the base of the ridged plains, which are typified by Hesperia Planum and cover about a third of the planet’s surface. In eastern Hesperia Planum, the ridged plains overlie early to mid Noachian aged cratered plateau materials (pictured left). The Hesperian’s upper boundary is more complex and"
"Titan and possible analogies to the prebiotic chemistry on the early Earth. The biology experiments used the full extraterrestrial spectrum of solar UV radiation and suitable cut-off filters to study both, the role of the ozone layer in protecting our biosphere and the likelihood of resistant terrestrial microorganisms (extremophiles) to survive in outer space. The latter studies will provide experimental data to the lithopanspermia hypothesis, and they will provide basic data to planetary protection issues. To get better insight into the habitability of Mars, one set of samples was exposed to simulated Martian conditions (UV-radiation climate, pressure, atmosphere), with and"
"most Earth-like of all the other planets in the Solar System. It is thought that Mars had a more Earth-like environment early in its history, with a thicker atmosphere and abundant water that was lost over the course of hundreds of millions of years. Given the foundations of similarity and proximity, Mars would make one of the most plausible terraforming targets in the Solar System. Side effects of terraforming include the potential displacement or destruction of indigenous life, even if microbial, if such life exists. The Martian environment presents several terraforming challenges to overcome and the extent of terraforming may"
"other small moons that suffered the fate expected of Phobos, and that the Martian crust as a whole shifted between these events. Deimos, on the other hand, is far enough away that its orbit is being slowly boosted instead, as in the case of our own Moon. The origin of the Martian moons is still controversial. Phobos and Deimos both have much in common with carbonaceous C-type asteroids, with spectra, albedo, and density very similar to those of C- or D-type asteroids. Based on their similarity, one hypothesis is that both moons may be captured main-belt asteroids. Both moons have"
"In the table, the days of the week are Sol Solis, Sol Lunae, Sol Martis, Sol Mercurii, Sol Jovis, Sol Veneris, Sol Saturni. The last day of Vrishika is an intercalary day that only occurs on leap years, much like February 29 in the Gregorian calendar. The Martian year is treated as beginning near the equinox marking spring in the northern hemisphere of the planet. Mars currently has an axial inclination similar to that of the Earth, so the Martian seasons are perceptible, though the greater eccentricity of Mars' orbit about the Sun compared with that of the Earth means"
"surface of its parent star. The team hypothesized that the planet's magnetosphere was transferring energy onto the star's surface, increasing its already high 7,760 °C temperature by an additional 400 °C. Several planets or dwarf planets in the Solar System (such as Neptune and Pluto) have orbital periods that are in resonance with each other or with smaller bodies (this is also common in satellite systems). All except Mercury and Venus have natural satellites, often called ""moons"". Earth has one, Mars has two, and the giant planets have numerous moons in complex planetary-type systems. Many moons of the giant planets"
"HR 8799 e </math></ref> HR 8799 e is a large exoplanet, orbiting the star HR 8799, which lies 129 lightyears from Earth. This gas giant is between 5 and 10 times the mass of Jupiter, the largest planet in the Solar System. Due to their young age and high temperature all four discovered planets in the HR 8799 system are large, compared to all gas giants in the Solar System. HR 8799 e is the fourth planet orbiting HR 8799 in order of discovery. It is a young, hot and massive gas giant, and is fairly close to its star,"
"stratigraphic context are unknown. Instead, absolute ages on Mars are determined by impact crater density, which is heavily dependent upon models of crater formation over time. Accordingly, the beginning and end dates for Martian periods are uncertain, especially for the Hesperian/Amazonian boundary, which may be in error by a factor of 2 or 3. Across many areas of the planet, the top of the Noachian System is overlain by more sparsely cratered, ridged plains materials interpreted to be vast flood basalts similar in makeup to the lunar maria. These ridged plains form the base of the younger Hesperian System (pictured"