NASA's Juno spacecraft made a close flyby of Jupiter's intriguing moon Europa in 2022, revealing potential hints of present day surface activity.
The spacecraft's Stellar Reference Unit (SRU), which is a star camera designed to assist Juno's onboard attitude determination, was used to image Europa's surface with high resolution while being lit up by Jupiter-shine, or sunlight scattered off Jupiter.
The SRU image from the flyby is explored in an article published in the journal JGR Planets on Dec. 22, 2023. The image shows an oddly-shaped area of the icy surface, measuring 23 miles by 42 miles (37 kilometers by 67 kilometers) and resembling a platypus. In other words, it exhibits a "body" part in the north and a "bill" part in the south. Both areas — which are joined by a cracked neck-like formation — contain large ice blocks that are each about 0.62 miles (1 km) in size and cast shadows.
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Comparisons with images of similar resolution from NASA's earlier Galileo spacecraft, which studied Jupiter from 1995 until 2003, suggest changes in the southern part of the "platypus" area. These hint that changes might have taken place on Europa's surface since the Galileo images were taken.
However, the team of authors, led by Heidi N. Becker of NASA's Jet Propulsion Laboratory (JPL), state that the evidence isn't conclusive due to differences in imaging quality and conditions.
The 2022 image also includes nearby low-albedo deposits which may be associated with subsurface liquid water, the researchers say. These dark stains may be associated with plumes thought to be spewing out water.
While not conclusive, however, the Platypus makes a compelling target for future missions such as NASA’s Europa Clipper and Europe's JUICE to investigate and possibly confirm present day surface activity on Europa.
JUICE launched in April of 2023 and will arrive at Jupiter in December 2031. Europa Clipper is set to launch on Oct. 6 this year on a Falcon Heavy rocket.
