This time-lapse video captures a portion of the path that tiny Phobos takes around Mars. Over the course of 22 minutes, Hubble snapped 13 separate exposures of the little Martian moon. The transitions between frames have been smoothed to illustrate continuous motion. Phobos completes an orbit in just 7 hours and 39 minutes, which is faster than Mars rotates. Rising in the Martian west, it runs three laps around the Red Planet in the course of one Martian day, which is about 24 hours and 40 minutes. It is the only natural satellite in the solar system that circles its planet in a time shorter than the parent planet’s day. Hubble photographed Phobos orbiting the Red Planet on May 12, 2016, when Mars was 50 million miles from Earth. This was just a few days before the planet passed closer to Earth in its orbit than it had in the past 11 years.
Publication: July 20, 2017