Astronomy Picture of the Day - Callisto: Dirty Battered Iceball

NASA ^ | 1 Sep, 2025 | Image Credit: NASA, JPL-Caltech, Voyager 2; Processing & License: Kevin M. Gill;

[MtnClimber]

Explanation: Its surface is the most densely cratered in the Solar System -- but what's inside? Jupiter's moon Callisto is a battered ball of dirty ice that is larger than the planet Mercury. It was visited by NASA's Galileo spacecraft in the 1990s and 2000s, but the recently reprocessed featured image is from a flyby of NASA's Voyager 2 in 1979. The moon would appear darker if it weren't for the tapestry of light-colored fractured surface ice created by eons of impacts. The interior of Callisto is potentially even more interesting because therein might lie an internal layer of liquid water. This potential underground sea is a candidate to harbor life -- similar with sister moons Europa and Ganymede. Callisto is slightly larger than Luna, Earth's Moon, but because of its high ice content is slightly less massive. ESA's JUICE and NASA's Europa Clipper missions are now headed out to Jupiter to better investigate its largest moons.

---

TOPICS: Astronomy; Astronomy Picture of the Day; Science
KEYWORDS: apod; astronomy; callisto; jupiter; nasa; science

[MtnClimber]

To be added or removed from the Astronomy Picture of the Day ping list please send me a request via "Private Reply" (Mail).

For more detail go to the link and click on the image for a high definition image. You can then move the magnifying glass cursor then click to zoom in and click again to zoom out. When zoomed in you can scan by moving the side bars on the bottom and right side of the image.

[MtnClimber]

[MtnClimber]

Pinging the APOD list

🪐 🌟 🌌 🍔

[No name given]

Wow.

[telescope115]

It looks like our kitchen floor after making pizza dough😛

[TigersEye]

The title says Callisto is battered so it might be a similar process.

[ridesthemiles]

PERFECTLY ROUND