NASA released a video of the photobomb on Thursday, which they captured during 22 minutes of imaging in May 2016. At the time, Mars was positioned just 50 million miles from Earth, its nearest distance in more than a decade. Scientists sought to capitalize on the close alignment to image Mars’ deep gorges and plentiful mountains, but what NASA has released first is this shot of Phobos tumbling through space. The little moon races around Mars every seven hours and 40 minutes, completing three orbits each Martian day.
Phobos looks like a big, rocky football, but its unique shape couldn’t be captured from 50 million miles away. It’s one of the smallest moons in the solar system, just 16.5 miles long and 13.5 miles wide. That’s small enough to “fit comfortably inside the Washington D.C. Beltway,” according to NASA.
Phobos is a doomed moon, as it’s being gravitationally stretched by Mars. Long grooves run across the moon, which are telltale signs of the incessant tugging and pulling from Mars. Scientists suspect that this gravitational havoc will one day rip Phobos apart, perhaps in 30 million years, littering the planet with rocky debris — and possibly raining down on any Martian civilization humans have built in the meantime.
The origins of Phobos’ deformed state will likely never be known. NASA scientists suggest it’s the result of dust and rocks that gravity has jammed together. Or perhaps Phobos once held a traditional spherical moon shape, but was bludgeoned by an asteroid impact and left as it is today, a diminutive, warped moon.