NASA's Perseverance rover has given us an otherworldly skywatching treat — the minuscule Mars moon Deimos, twinkling in the dusty Red Planet skies.
"Skywatching is fun no matter where you are. I took this short time-lapse movie to watch for clouds and caught something else: look closely and you'll see Deimos, one of two moons of Mars," Perseverance team members wrote via the mission's official Twitter account (opens in new tab) Friday (Aug. 20).
Perseverance, which landed inside the 28-mile-wide (45 kilometers) Jezero Crater in February, usually has its head down, studying Red Planet rocks and dirt. The rover's main tasks, after all, involve hunting for signs of ancient Mars life and collecting dozens of samples for future return to Earth.
But the rover does look up from time to time, and not just to study clouds. In April and May, for example, Perseverance helped document the first few flights of its traveling companion, NASA's 4-pound (1.8 kilograms) Ingenuity helicopter. Ingenuity is still going strong — the pioneering little chopper recently aced its 12th Martian sortie — but Perseverance began focusing on its own science work a few months ago.
The 7.7-mile-wide (12.4 kilometers) Deimos orbits 14,576 miles (23,458 km) above Mars, completing one nearly circular lap around the planet every 30 hours. Mars' other moon, Phobos, is about 14 miles (22 km) in diameter and orbits at an altitude of just 5,738 miles (9,234 km). Most astronomers think both satellites are asteroids that were captured by Mars' gravity (opens in new tab).
For comparison, Earth's moon is 2,159 miles wide (3,475 km) wide and lies 238,900 miles (384,470 km) from our planet on average. Our moon likely coalesced from material blasted into space by a titanic collision more than 4.4 billion years ago involving the proto-Earth and a Mars-size body called Theia, scientists say.
NASA Mars rovers have caught glimpses of the planet's two tiny moons before. For example, Curiosity has captured multiple shots of Phobos and Deimos since touching down on the floor of Gale Crater in August 2012. Curiosity's views include amazing time-lapse videos of each moon passing in front of the sun, causing partial solar eclipses.
Mike Wall is the author of "Out There (opens in new tab)" (Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook.