Key facts
- Category
- Moons
- Object class
- Small irregular moon
- Scale fact
- 22 kmmean diameter
- Host
- Mars
Phobos
22 kmmean diameter
Visual creditMars Reconnaissance Orbiter 2008 / NASA / JPL-Caltech / University of Arizona / Public domainSource: Wikimedia Commons
Details
Phobos is the larger, inner moon of Mars, a dark rubble-covered body dominated by the giant Stickney crater. NASA expects it to keep spiraling inward until it either breaks into a ring or crashes into Mars in about 50 million years.
Phobos orbits only about 6,000 kilometers above the Martian surface and completes roughly three circuits each day. Tidal interactions draw it about 1.8 meters closer to Mars per century. If that rate and the underlying model hold over geological time, the moon will either strike Mars or be torn into a ring in about 50 million years.
Links
- Universe journey
- Sun & inner planets
- Wikipedia
- Phobos on Wikipedia
Size neighbors
Objects near Phobos on the scale
On the logarithmic size axis, Phobos falls between Crab Pulsar and Calypso. The band uses nearby Small irregular moon records.
Sources
References for Phobos
Measurements and descriptive context are compiled by the Scale of Space team from the references below. If you find an error, please let us know.
- Phobos — Wikipedia
- Visual reference: Wikimedia Commons (Mars Reconnaissance Orbiter 2008 / NASA / JPL-Caltech / University of Arizona, Public domain)
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About
Scale of Space is a scroll-based journey through the universe, placing objects on a single logarithmic scale so you can compare size across an unbroken range.
Guides explain selected parts of that range, while focused views filter the objects by subject.