Stickney (crater)

Stickney is the largest impact crater on Phobos, the inner moon of Mars. This big crater is about 9 kilometers (5.6 miles) wide and covers much of the moon's surface. Craters like Stickney form when space objects crash into a planet or its moons, making deep pits and changing the land. Learning about Stickney helps scientists understand more about impacts in our solar system and how small space bodies work.

Naming

The Stickney crater is named after Chloe Angeline Hall Stickney. She was the wife of the astronomer who discovered Phobos. Her support helped her husband with his work. The crater got its name in 1973. This happened after images from the Mariner 9 spacecraft were studied. A group led by Carl Sagan studied the images.

Formation

There are two ideas about when the Stickney crater formed. If Phobos has been orbiting Mars for 4.3 billion years, then Stickney formed 4.2 billion years ago. If Phobos has only been orbiting for 3.5 billion years, then Stickney formed 2.6 billion years ago.

The impact that created Stickney sent out a lot of material, called ejecta. This material escaped Phobos's gravity and went into orbit around Mars. It stayed there for up to 1000 years before falling back to Phobos or creating smaller craters on the moon. Most of the smaller craters on Phobos were made by these secondary impacts.

Physical features

Stickney is the largest crater on Phobos, a moon of Mars. It is about 9 kilometers (5.6 miles) wide. Grooves and smaller craters spread out from Stickney. One idea is that these grooves were formed by the strong impact that made Stickney. Other ideas include that the grooves were made by material thrown up from impacts on Mars, by the pull of Mars's gravity, or by boulders rolling on Phobos's surface.

The crash that made Stickney was very strong and could have destroyed Phobos. But Phobos's porous, sponge-like structure helped it survive. Inside Stickney's walls, there are patterns caused by material sliding down into the crater. The southwest edge of Stickney has a bluish color, likely due to a thin layer of rock from Stickney and a smaller crater named Limtoc.