- 3308 - JUPITER - Europa, moon has water? Europa is one of Jupiter’s 79 moons. It is both the sixth closest moon to Jupiter and the sixth largest moon in the Solar System. It is an icy orb larger than the dwarf planet Pluto with a smooth, icy surface scarred by cracks and fissures
--------------------- 3308 - JUPITER - Europa, moon has water?
- Hubble Space Telescope recently revealed water vapor in the atmosphere of “Ganymede“, one of Jupiter’s moons. A new analysis of archival images and spectra has also revealed that water vapor is present in the atmosphere of Jupiter’s icy moon “Europa“.
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- The analysis found that a water vapor atmosphere is present only on one hemisphere of the moon Europa. This result advances our understanding of the atmospheric structure of icy moons, and helps lay the groundwork for upcoming science missions which will explore Jupiter’s icy moons.
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- Liquid water is a crucial ingredient in the complex chemistry that underpins all known forms of life. Europa’s subsurface ocean is warmed not by sunlight, but rather by the subtle flexing of the moon caused by Jupiter’s immense gravitational field. The presence of liquid water and a source of energy make Europa one of the most likely locations in the Solar System for potential habitability.
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- The surface of the moon is a bleak environment with an average temperature of −170 °C and only a tenuous atmosphere. Astronomers suspect that Europa harbors a vast ocean underneath its icy surface, which some scientists speculate could host extraterrestrial life.
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- Now an astronomer has discovered evidence for persistent water vapor in the atmosphere of Europa. Using a technique that recently resulted in the discovery of water vapor in the atmosphere of Jupiter’s moon Ganymede, an astronomer has found evidence of water in Europa’s trailing hemisphere, the portion of the moon that is always opposite to its direction of motion .
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- The observation of water vapor on Ganymede and on the trailing side of Europa advances our understanding of the atmospheres of icy moons.
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- To make this discovery, scientists delved into archival Hubble datasets, selecting ultraviolet observations of Europa from 1999, 2012, 2014 and 2015 while the moon was at various orbital positions. These observations were all taken with one of Hubble’s most versatile instruments, the Space Telescope Imaging Spectrograph (STIS).
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- These ultraviolet STIS measurements determined the abundance of oxygen, one of the constituents of water, in Europa’s atmosphere, and by interpreting the strength of emission at different wavelengths he was able to infer the presence of water vapor.
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- Previous observations of water vapor on Europa have been associated with transient plumes erupting through the ice, analogous to geysers here on Earth but more than 100 kilometers high. The phenomena seen in these plume studies were apparently transient inhomo-geneities or blobs in the atmosphere.
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- The new result show similar amounts of water vapor to be present spread over a larger area in observations spanning from 1999 to 2015. This suggests the long-term presence of a water vapor atmosphere on Europa’s trailing hemisphere. Despite the presence of water vapor on Europa’s trailing hemisphere there is no indication of water on the leading hemisphere of Europa.
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- “JUpiter ICy moons Explorer” (JUICE) mission is being prepared for a tour of Ganymede, Callisto and Europa, Jupiter’s three largest icy moons. JUICE is expected to launch in 2022 and arrive at Jupiter in 2031. The probe will carry an advanced suite of instruments and will spend at least three years making detailed observations of the Jovian system.
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- Europa will also be visited by a NASA mission, “Europa Clipper“, which will perform a series of flybys of the moon and investigate its habitability, as well as selecting a landing site for a future mission.
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- This discovery and the insights from upcoming missions such as JUICE will improve our understanding of potentially habitable environments in the Solar System. Understanding the formation and evolution of Jupiter and its moons also helps astronomers gain insights into Jupiter-like exoplanets around other stars.
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- Europa is tidally locked, which means that it takes the same amount of time to revolve on its own axis as it does to orbit Jupiter. This means that the same hemisphere of Europa always faces Jupiter, and that the same hemisphere of the moon is always facing away from the direction that Europa is traveling along its orbit.
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- Earth’s Moon is also tidally locked, which is why we always see the same face of the Moon in the night sky.
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- October 18, 2021 EUROPE - Jupiter’s moon 3308
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