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Science Coronavirus Coverage What families can do now that kids are getting the vaccine. Magazine How one image captures 21 hours of a volcanic eruption. Some of the ions are pulled into Jupiter's upper atmosphere and create auroras. An example of this activity was spotted by the Hubble Space Telescope , which revealed the influences of Io and another Jovian moon, Ganymede, in Jupiter's auroras in The sulfur dioxide envelope of gas freezes up while Io is in the shadow of Jupiter every day.
When Io comes back into sunlight, the freezing sulfur dioxide converts to gas once more. Scientists long suspected this phenomenon exists, but it was only after this new study — which saw Io's atmosphere in the dark for the first time — that researchers confirmed it. Io's environment has come under intense scrutiny in recent years as scientists try to explain why the moon has the most active volcanoes in the solar system. The recent findings involve both observations of the moon and modeling of the interior, which can only be inferred.
A study explained why Io's most prolific volcanoes appear to be offset from where scientists expected they would be. While previous models suggested that the zones with the most intense heating would have more active volcanoes, the actual Io had its most active ones farther east.
The study suggests that if there was an ocean mixed with molten and solid rock underneath the moon, the rock portions would rub against each other and create the offset zones scientists observed. However, the existence of a molten ocean came into doubt with a study , which showed that some auroras we can see in Io's atmosphere would have been damped out by an underground ocean.
In other words, we can only see the auroras because the moon likely has no molten ocean, the study concluded. Insights into Io's surface may also come from a map published by the U. Geological Survey — the first to include the entire surface. The researchers said that volcanic activity would be among the things that could be studied with this map. The imagery includes observations from the Voyager 1 and Voyager 2 spacecraft, as well as Galileo.
While there is no mission specifically planned to look at Io, other missions are now in the vicinity of the moon — such as the aforementioned Juno spacecraft — or will be in future years. Meanwhile, observations continue from the ground; sometimes Io's volcanoes are violent enough to produce spectacular pictures even from so far away.
Join our Space Forums to keep talking space on the latest missions, night sky and more! And if you have a news tip, correction or comment, let us know at: community space. Kim Ann Zimmermann. The righthand image above displays the lava flowfield of Culann Patera. These flows spill out on all sides of a central caldera. The variegated colors of the flows are most likely related to the interaction of the hot lava with SO 2 -rich debris on the ground surface as well as SO 2 -rich ash fall.
Some of these silicate lavas might be invasive flows that have been colored by interaction with the overlying sulfur-rich deposits.
The region confined to the yellow box the image above is blown up in the image shown here. The summit caldera of Culann Patera appears to be the source of a lava tube that feeds the large, dark green flow to the west.
The axis of the western part of the flow is marked by what appears to skylights lying above the tube's continuation. These features are typical of basalt lavas found on Earth. Lava composition is partly a function of the temperature of the melt. There has been some speculation that some of the lavas may be composed of liquid sulfur. Sulfur, however, boils vigorously on Io's surface at at about degrees Centigrade.
Therefore, the lavas on Io are certainly of a silicate composition. High-temperature lavas on earth have a mafic composition rich in magnesium and relatively depleted in silica.
The extraordinarily high temperatures of the lavas on Io suggest that they are of an ultramafic composition. The eruption of ultramafic lavas on Earth has been rare in the recent geologic past. These hot, ultramafic lavas are capable of melting other rock types as they travel on planetary surfaces.
Thermal erosion by ultramafic lavas are probably responsible for generating the sinuous rilles we see on the moon, and similar featuers may yet be found on Io. Volcanic plume March 4, taken by Voyager spacecraft. Volcanic plume July 3, taken by Galileo spacecraft. Pillan Petera arrow on April 4, Pillan Petera arrow on September 19,
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