Juno picks up hints of activity on Jupiter’s icy moon Europa

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 in high resolution while being lit up by sunlight scattered off Jupiter. The SRU image from the flyby is explored in an article published in the journal JGR Planets on 22 December 2023. The image shows an oddly shaped area of the icy surface, measuring 37 by 67 kilometres (23 by 42 miles) 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 one kilometre (0.62 miles) in size and cast shadows.

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, states 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.