Perseverance Spots 'Googly Eye' Eclipse on Mars

 

NASA's Perseverance rover recently recorded a solar occultation event on Mars, as the Martian moon Phobos eclipsed a portion of the Sun. Credit: NASA/JPL-Caltech/ASU/MSSS 

This anomalous phenomenon, characterized by its distinctive 'googly eye' appearance, has yielded significant information regarding the orbital parameters and long-term behavior of Mars' moons.

A Martian Eclipse: Perseverance Captures a Cosmic Eye

NASA's Perseverance rover, stationed on the Red Planet, recently witnessed a truly unique celestial spectacle. The rover's Mastcam-Z instrument captured a striking image of Mars' moon, Phobos, eclipsing the Sun.

On September 30th, 2023, during the 1,285th Martian day of its mission, Perseverance was treated to this cosmic show. As Phobos, a potato-shaped moon, transited directly between Mars and the Sun, it cast a dark shadow across the Martian surface. The image captured by the rover resembles a giant, otherworldly "googly eye," with Phobos forming the pupil and the Sun's disc serving as the iris.

This rare event, known as a solar transit, offers scientists a valuable opportunity to study the dynamics of Mars' moons and their gravitational influence on the planet. By analyzing the precise timing and path of Phobos' shadow, researchers can gain insights into the moon's orbit and its potential impact on Mars' geological features.

Utilizing its Mastcam-Z camera, NASA's Perseverance rover successfully captured a Phobos transit on September 30, 2024, during the 1,285th Martian sol. This marks the latest in a series of such events observed by the rover since its landing at Jezero Crater in February 2021. The video, accelerated by a factor of four, presents both the transit and the eclipse in real time. Credit: NASA/JPL-Caltech/ASU/MSSS

Significance of Phobos in History and Astronomy

Discovered by Asaph Hall in 1877, Phobos, the larger of Mars' two moons, is named after the Greek god of fear. This irregularly shaped satellite, with a maximum diameter of approximately 17 miles (27 kilometers), is significantly smaller than Earth's Moon. Its smaller companion, Deimos, is even less substantial.

Phobos is the larger of Mars' two moons, and it is the closest moon to Mars. It is also the only moon in the Solar System that is closer to its planet than any other moon. Phobos is tidally locked to Mars, which means that the same side of Phobos always faces Mars. As a result, Phobos orbits Mars in about 7 hours and 39 minutes.

Phobos is slowly moving closer to Mars, and it is expected to crash into Mars in about 50 million years. When Phobos crashes into Mars, it will create a crater that is about 10 kilometers in diameter.

Deimos is the smaller of Mars' two moons, and it is the farthest moon from Mars. It is also the smallest moon in the Solar System. Deimos is about 12 kilometers in diameter, and it is about 23,460 kilometers from Mars. Deimos is tidally locked to Mars, which means that the same side of Deimos always faces Mars. As a result, Deimos orbits Mars in about 30 hours and 18 minutes.

NASA’s Perseverance Mars rover used its Mastcam-Z camera system to shoot video of Phobos, one of Mars’ two moons, eclipsing the Sun. It’s the most zoomed-in, highest-frame-rate observation of a Phobos solar eclipse ever taken from the Martian surface. Credit: NASA/JPL-Caltech/ASU/MSSS/SSI

Exploring the Martian Skies

Phobos’ orbit aligns almost perfectly with Mars' equator and is relatively close to the planet's surface, allowing for transits of the moon on most days of the Martian year. With a rapid orbit taking about 7.6 hours to complete a full revolution around Mars, each transit of Phobos typically lasts around 30 seconds.

This isn’t the first time a NASA rover has observed Phobos blocking sunlight. Since landing in Jezero Crater in February 2021, Perseverance has recorded several transits of Phobos (see images above and below). Curiosity captured a video of a transit in 2019, and Opportunity took an image in 2004.

By analyzing these images, scientists can enhance their understanding of Phobos’ orbit and its gradual changes. The moon is gradually drifting closer to Mars, with predictions suggesting it could collide with the planet in about 50 million years.

NASA’s Perseverance Mars rover used its Mastcam-Z camera to capture the silhouette of Phobos, one of the two Martian moons, as it passed in front of the Sun on February 8, 2024, the 1,056th Martian day, or sol, of the mission. This is one of several transits of Phobos that NASA’s Mars rovers have captured. By comparing the various recordings, scientists can refine their understanding of the potato-shaped moon’s orbit, learning how it’s changing. Eons from now, Phobos’ orbit is expected to eventually send the moon toward the Red Planet’s surface. Credit: NASA/JPL-Caltech/ASU/MSSS/SSI

Mission Goals and Collaborations of Perseverance

The Mars 2020 Perseverance rover, overseen by NASA’s Jet Propulsion Laboratory in California, is a groundbreaking mission dedicated to astrobiology and the exploration of Mars. One of Perseverance’s main objectives is to search for evidence of ancient microbial life, offering valuable insights into the planet’s geological history and climate. This mission represents the first effort to collect and store Martian rock and regolith, with plans for future NASA and ESA missions to retrieve these samples and bring them back to Earth for in-depth analysis.

Equipped with state-of-the-art scientific instruments, Perseverance features the Mastcam-Z camera system, managed by Arizona State University in collaboration with Malin Space Science Systems and the Niels Bohr Institute. This camera system enables the capture of high-resolution images and supports the mission’s geological research. Perseverance is a key component of NASA’s broader Moon to Mars exploration strategy, where Artemis missions to the Moon will pave the way for eventual human exploration of Mars.