July 20 (UPI) -- A new miniature movie shows the transit of Phobos, one of Mars' two moons, around the Red Planet.
Last year, the Hubble Space Telescope captured several pictures of the diminutive moon as it orbited Mars. Recently, scientists at NASA turned the photos -- 13 exposures taken over the course of 22 minutes -- into a time-lapse video of the Martian moon's orbital path.
Phobos' oblong shape resembles a potato, or a football. At just 17 miles in length, it is one of the smallest moons in the solar system. The mini moon completes a single orbit in just more than seven hours, faster than the Red Planet completes a single rotation.
Researchers aren't entirely sure how Phobos formed. Some suggest a collection of rubble came together over time, pulled together by the gravity of Mars. The rubble is held together by a thin layer of crust. It's also possible the rocky fragments making up Phobos' core are the remnants of a once-larger moon destroyed by a violent collision.
Other scientists have argued Phobos and its even smaller sibling, Deimos, are asteroids from the Kuiper belt. But others say their orbits are too stable. Space rock captured by larger bodies typically boast more erratic orbital paths.
The images used to create the newly released video were recorded on May 12, 2016, as the Red Planet passed within 50 million miles of Earth. A few days later, Mars' orbit positioned the Red Planet closer to Earth than it had been in 11 years.