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.
12.5 km average circumference. Good place to practice running a half marathon. Might need extra oxygen.
Deimos’s escape velocity is only 5.8 m/s. A stone dropped from waist height would take around 30 seconds to reach the ground.
Jonathan Swift and the moons of Mars
David Darling
https://www.daviddarling.info/encyclopedia/S/Swift.html
How did Jonathan Swift predict mars moon speeds?
Ian_Brooks
June 24, 2009
https://www.physicsforums.com/threads/how-did-jonathan-swift-predict-mars-moon-speeds.321709/
My first encounter with this was here:
Jonathan Swift and the Moons of Mars
Ken D. Moss
Kronos vol.0804
Summer 1983
There was a sci fi story where explorers found the third moon that was at such a low altitude that it cut through mountains.
Three moons
phobos
demos
bottom most