Scientists also saw an aurora stretching across Ganymede.
REPUBLIKA.CO.ID, JAKARTA — Mission Juno belonging to the American Space Agency (NASA) passed within 1,000 kilometers of Jupiter’s largest moon Ganymede in June 2021. Scientists are still deciphering what was found in flyby that.
Two previous missions, Voyager 1 in 1979 and the Galileo spacecraft in the mid-1990s, had imaged Ganymede, the largest moon in the solar system. Unfortunately, some of those images were taken at less than ideal angles, leaving large blank spots unknown to scientists.
Today, technology has improved dramatically since the mission was launched. Scientists were thrilled when NASA’s Jupiter rover Juno revealed the crater-covered surface of the moon in the greatest detail ever. In the image, scientists see a shimmering aurora stretching between Ganymede’s poles and the equator.
These images outline a large number of new features on Ganymede’s surface, including a 100-kilometer-wide impact crater, said Geoffrey Collins, a geologist at Wheaton College in Massachusetts.
“We missed some very large impact craters that we couldn’t see in the Voyager data,” Collins said SpaceTuesday (22/3/2022).
“This should be a cautionary tale for trying to map something out from just one image with one lighting angle, one point of view. We missed this massive 100-kilometer crater which is very clear in the JunoCam data. One more thing, the crater is a little less clear, which is about 110 kilometers wide,” he said.
The images also reveal several smaller craters, 40 to 50 km wide. Scientists believe there are several features that may be the result of the Ganymede volcanic activity.
“We’ve found caldera-like features, similar to those we’ve seen previously in other parts of Ganymede,” Collins said.
A caldera is a volcanic crater. In Ganymede’s case it was most likely created by cryvolcano which ejects frozen water and gas from the moon’s interior.
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