For the first time ever, scientists have captured images of a moon passing directly in front of another as seen from the surface of an alien planet.
Normally, we're used to seeing the Curiosity rover take pictures of the Martian surface. But NASA recently had the mobile science lab point its Mastcam camera skywards, resulting in a series of 41 images.
The photographs were then stitched together to create this video, where Phobos can clearly be seen passing over the smaller moon, Diemos. You can even see Phobos's craters.
No previous images from any of the Martian missions on the surface caught one moon eclipsing the other.
Phobos has a diameter less than 1% the diameter of Earth's moon, but it orbits much closer to Mars than our moon's distance from Earth. As seen from the surface, Phobos looks about half as wide as what Earth's moon looks like to viewers on Earth.
This graphic offers a comparison of how big the moons of Mars appear to be, as seen from the surface of Mars, in relation to the size that Earth's moon appears to be when seen from the surface of Earth. Credit: NASA/JPL-Caltech/Malin Space Science Systems/Texas A&M Univ.