How Deep Is Europa's Ice? NASA Finally Measured It

If you wanted to drill into Europa's hidden ocean, where would you start? A new map suggests: right under the chaos. In September 2022, NASA's Juno flew 360 km above Jupiter's moon Europa and listened to its ice with a microwave radiometer. For a strip of the moon, the answer was a cold, rigid shell about 29 km thick, give or take 10, assuming pure ice. Juno also found small cracks or pores in the top few hundred meters, too small and shallow to link the surface and the ocean on their own. A second team, led by Alyssa Rhoden (Southwest Research Institute), used that one strip to anchor models of tidal heating across the whole moon. With even heat from below, the shell comes out 21 to 31 km thick; with uneven heat from the ocean, 18 to 36 km. In the runs with strong tidal heating, the thinnest ice lines up with Europa's chaos terrain, the opposite of earlier predictions. See figure one. The conditions matter: the Juno number assumes pure ice (a little salt makes it about 5 km thinner) and measures only the rigid top layer, and everything outside Juno's strip is a model, not a measurement. NASA's Europa Clipper arrives in 2030 with an ice-penetrating radar to test it. Chapters 0:00 This is Europa's chaos 0:22 An ocean under the ice 0:35 How thick? The old range 0:49 Thin shell or thick shell 1:01 Juno flies by 1:20 Listening to ice with microwaves 1:40 See figure one: 29 ± 10 km 2:05 Cracks in the top of the ice 2:20 One strip of one moon 2:33 Rhoden's map 2:50 21 to 31 km 3:05 The thinnest ice, under the chaos 3:22 Why drill here 3:33 Still about 20 km 3:46 The conditions 4:13 Europa Clipper Sources Levin, S. M., Zhang, Z., Bolton, S. J. et al. (2026). Europa's ice thickness and subsurface structure characterized by the Juno microwave radiometer. Nature Astronomy 10, 84–91. doi:10.1038/s41550-025-02718-0 (CC BY 4.0) https://www.nature.com/articles/s4155... Rhoden, A. R. et al. (2026). Europa's ice shell thickness variations as constrained by Juno results. Icarus, 117325. doi:10.1016/j.icarus.2026.117325 DPS 58 press briefing summary, AAS Nova: https://aasnova.org/2026/10/28/dps-58... Also cited: Carr et al. 1998; Khurana et al. 1998; Kivelson et al. 2000; Greenberg et al. 1999; Pappalardo et al. 1998; Ojakangas & Stevenson 1989; Kang 2022; Blankenship et al. 2024. Credits Figure 1: Levin et al. 2026, Nature Astronomy (CC BY 4.0). Galileo images: NASA/JPL-Caltech (chaos terrain mosaic, Europa Clipper resources; PIA01403; PIA01127); Europa global view PIA19048, NASA/JPL-Caltech/SETI Institute. Jupiter: Cassini PIA04866, NASA/JPL/University of Arizona. Artist's impressions: Gemini (gemini-3-pro-image) plates and kie.ai motion; thumbnail heroes generated with Gemini (Juno referenced to NASA PIA20703); Juno rendering referenced to NASA PIA20703; chaos flyover referenced to the Galileo mosaic. Collage objects generated with Gemini. Charts drawn from published values. [LONG-FORM: no Short link needed here. After upload, set this video as the Related video on the Short.] See Figure 1: new studies, explained in plain language. Subscribe @seefigure1 #space #science #astronomy #Europa #Jupiter #planetaryscience #NASA #Juno #icymoons #oceanworlds #EuropaClipper #astrobiology #solarsystem #spacescience #sciencenews