What 'continental' moon of the Solar System has become the focus of extra-terrestrial life studies because its smooth surface suggests the presence of an ocean underneath?
"of the four Galilean moons. Despite this, its volcanoes could be energy resources for the other moons, better to colonize. The Artemis Project proposed a plan to colonize Europa. Scientists would inhabit igloos and drill down into the Europan ice crust, exploring any subsurface ocean. The report also discusses use of air pockets for human habitation. Ganymede is the largest moon in the Solar System. Ganymede is the only moon with a magnetosphere, but it is overshadowed by Jupiter's magnetic field. Ganymede receives about 8 rem of radiation per day. Due to its distance from Jupiter's powerful radiation belt, Callisto"
"The presence of an internal salty ocean in contact with the moon's rocky core, places Enceladus ""among the most likely places in the Solar System to host alien microbial life"". On June 30, 2014, NASA celebrated ten years of ""Cassini"" exploring Saturn and its moons, highlighting the discovery of water activity on Enceladus among other findings. In September 2015, NASA announced that gravitational and imaging data from ""Cassini"" were used to analyze the librations of Enceladus' orbit and determined that the moon's surface is not rigidly joined to its core, concluding that the underground ocean must therefore be global in"
"moon orbiting close to Saturn, notable for its extremely bright surface and the geyser-like plumes of ice and water vapor that erupt from its southern polar region. If Enceladus has liquid water, it joins Mars and Jupiter's moon Europa as one of the prime places in the Solar System to look for extraterrestrial life and possible future settlements. Other large satellites: Rhea, Iapetus, Dione, Tethys, and Mimas, all have large quantities of volatiles, which can be used to support settlements. The Kuiper belt is estimated to have 70,000 bodies of 100 km or larger. Freeman Dyson has suggested that within"
"south pole of this moon allow ice and gas from the ocean to escape to space where it has been sampled by mass spectrometers aboard the ""Cassini"" Saturn orbiter. Titan's ocean is the deepest, at 50 to 100 km, and no evidence for plumes or ice volcanism exist on the surface. A host of other bodies in the outer Solar System are inferred by a single type of observation or by theoretical modeling to have subsurface oceans and these include: Ganymede, Dione, Pluto, Triton, and Ceres, as well as Callisto, and Mimas. Astrobiology mission concepts to water worlds in the"
"the scientists. Another planetary body that could potentially sustain extraterrestrial life is Saturn's largest moon, Titan. Titan has been described as having conditions similar to those of early Earth. On its surface, scientists have discovered the first liquid lakes outside Earth, but these lakes seem to be composed of ethane and/or methane, not water. Some scientists think it possible that these liquid hydrocarbons might take the place of water in living cells different from those on Earth. After Cassini data was studied, it was reported on March 2008 that Titan may also have an underground ocean composed of liquid water"
"surface is striated by cracks and streaks, whereas craters are relatively rare. In addition to Earth-bound telescope observations, Europa has been examined by a succession of space probe flybys, the first occurring in the early 1970s. Europa has the smoothest surface of any known solid object in the Solar System. The apparent youth and smoothness of the surface have led to the hypothesis that a water ocean exists beneath it, which could conceivably harbour extraterrestrial life. The predominant model suggests that heat from tidal flexing causes the ocean to remain liquid and drives ice movement similar to plate tectonics, absorbing"
"in 2010-2011 confirmed a subsurface ocean. While previously believed to be localized, most likely in a portion of the southern hemisphere, evidence revealed in 2015 now suggests the subsurface ocean is global in nature. In addition to water, these geysers from vents near the south pole contained small amounts of salt, nitrogen, carbon dioxide, and volatile hydrocarbons. The melting of the ocean water and the geysers appear to be driven by tidal flux from Saturn. A subsurface saline ocean is theorized to exist on Ganymede, a moon of Jupiter, following observation by the Hubble Space Telescope in 2015. Patterns in"
"is thought unlikely. In contrast, some of Jupiter's moons may have habitats capable of sustaining life. Scientists have indications that heated subsurface oceans of liquid water may exist deep under the crusts of the three outer Galilean moons—Europa, Ganymede, and Callisto. The EJSM/Laplace mission is planned to determine the habitability of these environments. Jupiter's moon Europa has been subject to speculation about the existence of life due to the strong possibility of a liquid water ocean beneath its ice surface. Hydrothermal vents on the bottom of the ocean, if they exist, may warm the ice and could be capable of"
"probe detected carbon, hydrogen, nitrogen and oxygen—all key elements for supporting life—during its 2005 flyby through one of Enceladus's geysers spewing ice and gas. The temperature and density of the plumes indicate a warmer, watery source beneath the surface. Titan, the largest moon of Saturn, is the only known moon in the Solar System with a significant atmosphere. Data from the ""Cassini–Huygens"" mission refuted the hypothesis of a global hydrocarbon ocean, but later demonstrated the existence of liquid hydrocarbon lakes in the polar regions—the first stable bodies of surface liquid discovered outside Earth. Analysis of data from the mission has"
"and ammonia. Additionally, Saturn's moon Enceladus may have an ocean below its icy surface and, according to NASA scientists in May 2011, ""is emerging as the most habitable spot beyond Earth in the Solar System for life as we know it"". On 27 June 2018, astronomers reported the detection of complex macromolecular organics on Enceladus. Measuring the ratio of hydrogen and methane levels on Mars may help determine the likelihood of life on Mars. According to the scientists, ""...low H/CH ratios (less than approximately 40) indicate that life is likely present and active."" Other scientists have recently reported methods of"
"and presence of water. In addition to Europa, Lakdawalla cited Enceladus (a moon of Saturn), due to its active salty geysers: ""Those geysers are salty – it's a salt water ocean, so we basically have a world that is conveniently venting its ocean out into space. You don't even have to land – you can just fly right through that plume and check to see what kinds of cool chemistry is happening there. So yeah, I think Enceladus would be a really cool place to explore for life."" Lakdawalla has been interviewed on topics such as China's Jade Rabbit moon"
"penetration. It offers systems for obstacle avoidance, target detection, and acoustic navigation in ice. Enceladus Explorer Enceladus Explorer (EnEx) is a planned interplanetary orbiter and lander mission equipped with a subsurface maneuverable ice melting probe suitable to assess the existence of life on Saturn's moon Enceladus. The astrobiology Enceladus Explorer project is funded by the German Aerospace Center (DLR), and is carried out by a research consortium of seven German universities. This collaborative project was started on 22 February 2012. Enceladus is a small icy moon, seemingly similar in chemical makeup to comets, with jets or geysers of water erupting"
"queen of Crete, though the name did not become widely used until the mid-20th century. It has a smooth and bright surface, with a layer of water surrounding the mantle of the planet, thought to be 100 kilometers thick. The smooth surface includes a layer of ice, while the bottom of the ice is theorized to be liquid water. The apparent youth and smoothness of the surface have led to the hypothesis that a water ocean exists beneath it, which could conceivably serve as an abode for extraterrestrial life. Heat energy from tidal flexing ensures that the ocean remains liquid"
"smallest of the four Galilean satellites and the second closest to Jupiter. It is theorized to have an ocean of liquid water underneath its icy surface; the thickness of the ice is much debated. The probable presence of the water ocean has made it a favored location for modern fictional speculation about extraterrestrial life in the Solar System. Ganymede is the third of the Galilean moons from Jupiter. It is the largest moon in the Solar System, bigger than the planet Mercury (though less massive), almost 52% larger than the diameter of the Moon and with twice its mass. It"
"floor, where the moon's ocean meets the underlying rock, a prime habitat for life. The geysers could provide easy access for sampling the moon's subsurface ocean, and if there is microbial life in it, ice particles from the sea could contain the evidence astrobiologists need to identify them. An organic-rich world, Titan has a methane cycle comparable in atmospheric and geological processes to Earth's water cycle. The JET orbiter mission concept was proposed in 2011 by the Jet Propulsion Laboratory to NASA's Discovery Program Mission #13. During the orbiter's one-year mission, it would perform high-resolution mass spectroscopy mapping that would"
"for comparison with other more active and complex worlds. It is speculated that there could be life in Callisto's subsurface ocean. Like Europa and Ganymede, as well as Saturn's moons Enceladus, Mimas, Dione and Titan, a possible subsurface ocean might be composed of salt water. It is possible that halophiles could thrive in the ocean. As with Europa and Ganymede, the idea has been raised that habitable conditions and even extraterrestrial microbial life may exist in the salty ocean under the Callistoan surface. However, the environmental conditions necessary for life appear to be less favorable on Callisto than on Europa."
"Enceladus Explorer Enceladus Explorer (EnEx) is a planned interplanetary orbiter and lander mission equipped with a subsurface maneuverable ice melting probe suitable to assess the existence of life on Saturn's moon Enceladus. The astrobiology Enceladus Explorer project is funded by the German Aerospace Center (DLR), and is carried out by a research consortium of seven German universities. This collaborative project was started on 22 February 2012. Enceladus is a small icy moon, seemingly similar in chemical makeup to comets, with jets or geysers of water erupting from its surface that might be connected to active hydrothermal vents at its subsurface"
"combined with evidence of ongoing cryovalcanic activity. Scientists' consensus is that a layer of liquid water exists beneath Europa's surface, and that heat energy from tidal flexing allows the subsurface ocean to remain liquid. The first hints of a subsurface ocean came from theoretical considerations of tidal heating (a consequence of Europa's slightly eccentric orbit and orbital resonance with the other Galilean moons). Scientists used gravitational measurements from the Cassini spacecraft to confirm a water ocean under the crust of Enceladus. Such tidal models have been used as theories for water layers in other Solar System moons. According to at"
"restricted to the surfaces of planets. The three most likely candidates for life in the Solar System are the planet Mars, the Jovian moon Europa, and Saturn's moons Titan, and Enceladus. Mars, Enceladus and Europa are considered likely candidates in the search for life primarily because they may have underground liquid water, a molecule essential for life as we know it for its use as a solvent in cells. Water on Mars is found frozen in its polar ice caps, and newly carved gullies recently observed on Mars suggest that liquid water may exist, at least transiently, on the planet's"
"on the icy crust of Europa. The presence of the minerals may have been the result of a collision with an asteroid or comet according to the scientists. The ""Europa Clipper"", which would assess the habitability of Europa, is planned for launch in 2025. Europa's subsurface ocean is considered the best target for the discovery of life. Titan and Enceladus have been speculated to have possible habitats supportive of life. Enceladus, a moon of Saturn, has some of the conditions for life, including geothermal activity and water vapor, as well as possible under-ice oceans heated by tidal effects. The ""Cassini–Huygens"""
"an abundance of volatiles that may support colonization efforts. Titan is suggested as a target for colonization, because it is the only moon in the Solar System to have a dense atmosphere and is rich in carbon-bearing compounds. Titan has ice water and large methane oceans. Robert Zubrin identified Titan as possessing an abundance of all the elements necessary to support life, making Titan perhaps the most advantageous locale in the outer Solar System for colonization, and saying ""In certain ways, Titan is the most hospitable extraterrestrial world within our solar system for human colonization"". Enceladus is a small, icy"
"Oceanus (Titan orbiter) Oceanus is a NASA/JPL orbiter mission concept proposed in 2017 for the New Frontiers mission #4, but it was not selected for development. If selected at some future opportunity, ""Oceanus"" would travel to Saturn's moon Titan to assess its habitability. Studying Titan would help understand the early Earth and exoplanets which orbit other stars. The mission is named after Oceanus, the Greek god of oceans. Titan is a world of two oceans. One ocean is on the surface and consists of mainly liquid methane () and ethane (). The second ocean is under the surface and is"
"are thought to be able to support liquid water at their surfaces. Though in theory such giant planets could possess moons, the technology did not exist to detect moons around them, and no extrasolar moons had been detected. Planets within the zone with the potential for solid surfaces were therefore of much greater interest. The 2007 discovery of Gliese 581 c, the first super-Earth in the circumstellar habitable zone, created significant interest in the system by the scientific community, although the planet was later found to have extreme surface conditions that may resemble Venus. Gliese 581 d, another planet in"
"the program focuses on a fictional moon called Blue Moon, which orbits an enormous gas giant that is itself orbiting a binary star system. The Blue Moon is covered in life-giving water and an atmosphere so dense that enormous creatures hypothetically can take flight. The Blue Moon orbits a (a Jupiter-like planet that is cool enough to have visible rain clouds in its atmosphere) orbiting a close binary star system. The Blue Moon itself is roughly an earth mass but has an air pressure around three times that of Earth's at sea level. A distinguishing feature of Blue Moon is"
"from one planet to another via the panspermia theory. The search for extraterrestrial microbial life have focused mostly on Mars due to its promising environment and close proximity; however, other astrobiological sites include the moons Europa, Titan and Enceladus. All of these sites currently have or have had a recent history of possessing liquid water, which scientists hypothesize as the most consequential precursor for biological life. Europa and Enceladus appear to have large amounts of liquid water hidden beneath the layers of ice that covers their surfaces. Titan, on the other hand, is only planetary body besides Earth with liquid"
"its orbit, and its neighbor Europa may have a liquid ocean or icy slush underneath a frozen shell also due to power generated from orbiting a gas giant. Saturn's Titan, meanwhile, has an outside chance of harbouring life, as it has retained a thick atmosphere and has liquid methane seas on its surface. Organic-chemical reactions that only require minimum energy are possible in these seas, but whether any living system can be based on such minimal reactions is unclear, and would seem unlikely. These satellites are exceptions, but they prove that mass, as a criterion for habitability, cannot necessarily be"
"ocean. Surface features were observed by the ""Cassini"" spacecraft to systematically shift by up to between October 2005 and May 2007, which suggests that the crust is decoupled from the interior, and provides additional evidence for an interior liquid layer. Further supporting evidence for a liquid layer and ice shell decoupled from the solid core comes from the way the gravity field varies as Titan orbits Saturn. Comparison of the gravity field with the RADAR-based topography observations also suggests that the ice shell may be substantially rigid. The moons of Jupiter and Saturn are thought to have formed through co-accretion,"
"or reflected from the ground). The Moon has a southern polar star, δ Doradus, a magnitude 4.34 star. It is better aligned than Earth's Polaris (α Ursae Minoris), but much fainter. The Sun looks the same from the Moon as it does from Earth's orbit, somewhat brighter than it does from the Earth's surface, and colored pure white, due to the lack of atmospheric scattering and absorption. Since the Moon's axial tilt relative to its orbit around the Sun is nearly zero, the Sun traces out almost exactly the same path through the Moon's sky over the course of a"
"research concerns the atmosphere of Saturn's moon Titan, which is, according to NASA, ""a model for what the early Earth might have been like."" Titan has a thick, nitrogen-dominated atmosphere and is the only world in the solar system other than Earth known to possess stable liquid on its surface."" (Titan's seas are not water, however, but methane and ethane.) In 2015, Anderson reported her discovery of a chemically new, high-altitude ice cloud residing in Titan's south polar stratosphere during Titan's early southern winter season, chemically consistent with co-condensed hydrogen cyanide and benzene. During her 12-year tenure on the Cassini"
"of its substantial water content and fully differentiated interior In the 1970s, NASA scientists first suspected that Ganymede has a thick ocean between two layers of ice, one on the surface and one beneath a liquid ocean and atop the rocky mantle. In the 1990s, NASA's ""Galileo"" mission flew by Ganymede, confirming the moon's sub-surface ocean. An analysis published in 2014, taking into account the realistic thermodynamics for water and effects of salt, suggests that Ganymede might have a stack of several ocean layers separated by different phases of ice, with the lowest liquid layer adjacent to the rocky mantle."
"occurrence of some of the chaotic, and short lived, surface-water episodes throughout Martian history. Remote sensing of other planetary bodies has also indicated the presence of numerous hydrated mineral species, including sulfates, near various planetary surfaces, a prominent example of which is Jupiter’s moon Europa. The relatively smooth, and very young surface of Europa has been interpreted as evidence for a putative ocean beneath the moons icy surface, and is therefore suggestive of liquid brine at depth. Due to the cryospheric conditions present on Europa it is likely that any magnesium sulfate minerals present, and in contact with liquid water,"
"called Valhalla. Callisto is surrounded by an extremely thin atmosphere composed of carbon dioxide and probably molecular oxygen. Investigation revealed that Callisto may possibly have a subsurface ocean of liquid water at depths less than 300 kilometres. The likely presence of an ocean within Callisto indicates that it can or could harbour life. However, this is less likely than on nearby Europa. Callisto has long been considered the most suitable place for a human base for future exploration of the Jupiter system since it is furthest from the intense radiation of Jupiter. Fluctuations in the orbits of the moons indicate"
"Life on Titan Whether there is life on Titan, the largest moon of Saturn, is at present an open question and a topic of scientific assessment and research. Titan is far colder than Earth, and its surface lacks stable liquid water, factors which have led some scientists to consider life there unlikely. On the other hand, its thick atmosphere is chemically active and rich in carbon compounds. On the surface there are bodies of liquid methane and ethane, and it is likely that there is a layer of liquid water under its ice shell; some scientists speculate that these liquid"