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Der Baum im Herbstlicht & Das Leuchten des Waldes by Oliver Henze
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Galaxy UGC 2885 may be the largest one in the local universe. It is 2.5 times wider than our Milky Way and contains 10 times as many stars. This galaxy is 232 million light-years away, located in the northern constellation of Perseus.
Credit: NASA, ESA, and B. Holwerda (University of Louisville)
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Scientists' consensus is that a layer of liquid water exists beneath Europa's surface, and that heat from tidal flexing allows the subsurface ocean to remain liquid.
Europa's surface temperature averages about 110Β K (β160Β Β°C; β260Β Β°F) at the equator and only 50Β K (β220Β Β°C; β370Β Β°F) at the poles, keeping Europa's icy crust as hard as granite. 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). Galileo imaging team members argue for the existence of a subsurface ocean from analysis of Voyager and Galileo images.
The most dramatic example is "chaos terrain", a common feature on Europa's surface that some interpret as a region where the subsurface ocean has melted through the icy crust.
The thin-ice model suggests that Europa's ice shell may be only a few kilometers thick. However, most planetary scientists conclude that this model considers only those topmost layers of Europa's crust that behave elastically when affected by Jupiter's tides.
The Hubble Space Telescope acquired an image of Europa in 2012 that was interpreted to be a plume of water vapour erupting from near its south pole The image suggests the plume may be 200Β km (120Β mi) high, or more than 20 times the height of Mt. Everest.
So far, there is no evidence that life exists on Europa, but Europa has emerged as one of the most likely locations in the Solar System for potential habitability. Life could exist in its under-ice ocean, perhaps in an environment similar to Earth's deep-ocean hydrothermal vents. Even if Europa lacks volcanic hydrothermal activity, a 2016 NASA study found that Earth-like levels of hydrogen and oxygen could be produced through processes related to serpentinization and ice-derived oxidants, which do not directly involve volcanism.
In 2015, scientists announced that salt from a subsurface ocean may likely be coating some geological features on Europa, suggesting that the ocean is interacting with the seafloor. This may be important in determining if Europa could be habitable. The likely presence of liquid water in contact with Europa's rocky mantle has spurred calls to send a probe there.
Europa Clipper is an interplanetary mission in development by NASA comprising an orbiter. Set for a launch in October 2024, the spacecraft is being developed to study the Galilean moon Europa through a series of flybys while in orbit around Jupiter.
The Europa Lander is a proposed astrobiology mission concept by NASA to Europa, an icy moon of Jupiter. If funded and developed as a large strategic science mission, it would be launched in 2027 to complement the studies by the Europa Clipper orbiter mission and perform analyses on site. NASA's budget for fiscal year 2021 neither mandates nor allocates any funds to the mission leaving its future uncertain.
The objectives of the mission are to search for biosignatures at the subsurface β10 cm, to characterize the composition of non-ice near-subsurface material, and determine the proximity of liquid water and recently erupted material near the lander's location.
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The Colors of Saturn from Cassini Image Credit: NASA, ESA, JPL, ISS, Cassini Imaging Team; Processing & License: Judy Schmidt
Explanation: What creates Saturnβs colors? The featured picture of Saturn only slightly exaggerates what a human would see if hovering close to the giant ringed world. The image was taken in 2005 by the robot Cassini spacecraft that orbited Saturn from 2004 to 2017. Here Saturnβs majestic rings appear directly only as a curved line, appearing brown, in part from its infrared glow. The rings best show their complex structure in the dark shadows they create across the upper part of the planet. The northern hemisphere of Saturn can appear partly blue for the same reason that Earthβs skies can appear blue β molecules in the cloudless portions of both planetβs atmospheres are better at scattering blue light than red. When looking deep into Saturnβs clouds, however, the natural gold hue of Saturnβs clouds becomes dominant. It is not known why southern Saturn does not show the same blue hue β one hypothesis holds that clouds are higher there. It is also not known why some of Saturnβs clouds are colored gold.
β Source: apod.nasa.gov/apod/ap240623.html
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The European Southern Observatoryβs Very Large Telescope (ESOβs VLT) has taken the first ever image of a young, Sun-like star accompanied by two giant exoplanets. Images of systems with multiple exoplanets are extremely rare, and β until now β astronomers had never directly observed more than one planet orbiting a star similar to the Sun. The observations can help astronomers understand how planets formed and evolved around our own Sun.
The two gas giants orbit their host star at distances of 160 and about 320 times the Earth-Sun distance. This places these planets much further away from their star than Jupiter or Saturn, also two gas giants, are from the Sun; they lie at only 5 and 10 times the Earth-Sun distance, respectively. The team also found the two exoplanets are much heavier than the ones in our Solar System, the inner planet having 14 times Jupiterβs mass and the outer one six times.
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~ Orange and Brown ~
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Dione (moon of Saturn) 2005 and 2015
Credit: NASA/JPL-Caltech/SSI/Kevin M. Gill
Β My ambition is handicapped by laziness. -C. Bukowski Β Β Me gustan las personas desesperadas con mentes rotas y destinos rotos. EstΓ‘n llenos de sorpresas y explosiones. -C. Bukowski. I love cats. Born in the early 80's, raised in the 90's. I like Nature, Autumn, books, landscapes, cold days, cloudy Windy days, space, Science, Paleontology, Biology, Astronomy, History, Social Sciences, Drawing, spending the night watching at the stars, Rick & Morty. I'm a lazy ass.
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