Perseverance captures incredible views of Earth vanishing behind Martian moon Phobos—see photos here
NASA has shared a stunning image of an occultation between Earth and the Martian moon Phobos. The imagery was captured by the Perseverance rover on Mars on July 2 using the Mastcam-Z instrument and shows Earth, visible as a tiny speck of light, disappearing behind a crescent Phobos—the larger of the two moons of the Red Planet. An occultation happens when an object closer to the viewer has a larger apparent size and completely hides a distant object in the background.
“The composite image makes for a unique Earth self-portrait, taken from the surface of another planet, with a Phobos photobomb,” Justin Maki, the Mastcam-Z deputy principal investigator and imaging scientist for Perseverance at NASA’s Jet Propulsion Laboratory (JPL), said in a statement. Interestingly, this is the first time that Earth has been captured disappearing behind an object from the surface of another planet. Mastcam-Z co-investigator Mark Lemmon, who planned the observation and assembled the composite, said, “Phobos crosses the Martian sky three times a day, and Earth is visible for months at a stretch, but catching one directly behind the other takes planning and a little luck.”
The rover has captured multiple images that show different stages of the occultation. In the composite picture, Earth sweeps in from the left as a white dot and crosses behind Phobos before emerging again. Our planet was about 195 million miles (314 million kilometers) away from Mars when the pictures were taken. Phobos, on the other hand, appears roughly one-third the width of Earth’s Moon as seen from our planet.
Mars has another moon called Deimos. While Phobos measures 17 by 14 by 11 miles (27 by 22 by 18 kilometers) in size, Deimos measures 9.3 by 7.6 by 6.8 miles (15 by 12.2 by 11 kilometers). Phobos orbits Mars only 3,700 miles (6,000 kilometers) above the surface—which is the shortest distance of any known moon—and this has put it on a collision course with Mars. Scientists have estimated that in about 50 million years, it will either smash into Mars or break up into a ring.
While the latest observation involving Phobos was an occultation, it has also been captured during a transit—when a smaller-appearing object crosses the face of a large one. On February 8, 2024, Perseverance captured incredible images of Phobos transiting the Sun, offering scientists an opportunity to study the moon’s orbit and how it’s changing with time.
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