A day after the total solar eclipse seen from Earth, NASA's Mastcam-Z rover pointed its camera at the sun and captured the jagged silhouette of the moon Phobos. Such a transit provides not only an extraordinary sight, but also data on the moon's changing orbit and the interior structure of Mars.
A day after millions of people on Earth watched the total solar eclipse of August 12, 2026, a Mars A similar spectacle – but very different in its details. The SUV Presbyrans של NASA He pointed his camera at the sun and recorded the Phobos, the larger of Mars' two moons, passes in front of the bright disk.
The image was taken on August 13, 2026, the 1,948th Martian day of the Perseverance mission. According to NASA, it was received at 10:13:51 local solar time at the rover's operating site. The image was taken using the left camera of the Mastcam-Z system, a pair of zoom cameras mounted on the top of Perseverance's mast.
The image shows the Sun as a yellowish disk against a black background, while Phobos appears as a dark, irregular shadow covering part of it. The image was chosen by public vote as the Perseverance mission's "Picture of the Week" for the week of August 9-15.
Transit and not total eclipse
The event is sometimes described as "Eclipse "on Mars", but the more accurate term is transit - because Phobos is not large enough in the Martian sky to hide the entire disk of the Sun.
On Earth, there is an unusual geometric coincidence: although the Sun is about 400 times larger than the Moon, it is also about 400 times farther away, so the two bodies appear almost equal in size in the sky. When aligned properly, the Moon can completely block out the Sun, creating a total eclipse.
Although Phobos orbits Mars in a very low orbit, it is only about 27 kilometers across at its widest point. Therefore, it does not completely cover the sun. Instead of the relatively prolonged darkness that characterizes a total eclipse on Earth, its potato-shaped shadow quickly crosses the sun's surface.
The Mastcam‑Z system is equipped with special filters that greatly reduce the intensity of light reaching the sensors, similar to goggles used to view an eclipse. The filters allow the cameras to capture images of the Sun without the intense light flooding the image or damaging the detectors.
A moon that orbits Mars three times a day
Phobos is the inner and larger of Mars' two small moons. The other moon, Deimos, is smaller and more distant. Phobos orbits only about 6,000 kilometers above the surface of Mars and completes one orbit in about seven hours and 39 minutes—faster than the time it takes Mars to complete one rotation on its axis.
Therefore, an observer in a suitable location on Mars may see Phobos cross the sky several times a day. It rises in the west and sets in the east, in the opposite direction to the apparent motion of most moons in the planetary sky.
Transits across the Sun are very short. In a detailed observation by Perseverance in April 2022, the transit lasted just over 40 seconds. The images made it possible to identify not only Phobos' jagged shape, but also ridges and depressions along its contour and even sunspots on the Sun's surface.
What can we learn from a photograph of an eclipse?
The images aren't just meant to provide spectacular images of the Martian sky. Precise timing of Phobos' entry and exit from the sun allows scientists to measure its position in orbit with great precision.
NASA has been monitoring such transits since the Spirit and Opportunity rovers first photographed them in 2004. Curiosity has continued observations, and Perseverance’s Mastcam‑Z system provides magnified images at a higher frame rate.
Comparing observations collected over more than two decades allows us to track the tiny changes in Phobos' orbit. The moon is gradually approaching Mars, at a rate of a few centimeters per year. Within tens of millions of years, it is expected to break apart due to tidal forces and form a ring around Mars, or crash into the planet's surface.
The relationship also works in the opposite direction. Phobos' gravity exerts weak tidal forces on Mars, slightly deforming rocks in the crust and mantle. Measuring changes in the moon's orbit can provide information about the elasticity of the Martian interior and the properties of the materials that make up its crust and mantle.
A perspective from another world
Humans have never yet observed a solar eclipse from the surface of another planet. The images captured by Perseverance and other rover vehicles essentially give us a robotic vantage point into the skies of an alien world.
Perseverance landed inJezero Crater February 2021. Its main mission is to study the geology and ancient climate of Mars, search for possible signs of ancient microbial life, and collect rock and soil samples that could eventually reach Earth. However, it occasionally turns its cameras from the ground to the sky – reminding us that even from Mars, the constant movement of the solar system can be observed.
Questions and Answers
Was it a total solar eclipse on Mars? No. Phobos is too small to obscure the entire disk of the Sun. So, astronomically, it is more accurate to describe the event as a transit of Phobos across the Sun, although NASA and the media sometimes use the phrase "solar eclipse of Mars."
When was the picture taken? On August 13, 2026, on the 1,948th Martian day of the Perseverance mission, at 10:13:51 local solar time.
What camera did Perseverance use? The image was taken with the left camera of the Mastcam‑Z, a system of two zoomable cameras mounted at the top of the mast of the SUV.
Why do scientists photograph these transitions? The timing of the transits makes it possible to precisely calculate Phobos' orbit, track its gradual approach to Mars, and study how the tidal forces between it and Mars are affected by the properties of the planet's crust and mantle.
For the original publication: Opening the original publication
More on the subject on the science website
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- Giant plasma waves may help the solar wind strip away the Martian atmosphere
- After Falcon 9 stage hits the moon: NASA and SpaceX are looking at how to prevent the next incident
- Curiosity discovered a “sea” of polygonal cracks on Mars – and it’s unclear how they formed
- Falcon 9 stage likely hit the moon; confirmation will come from orbiting spacecraft images
One response
It's a shame that the updated photo doesn't appear in the article. The photo shown in the link leading to the article is from a similar eclipse that was taken two and a half years ago.
https://www.israelhayom.co.il/viralai/article/15259624
The current eclipse is shown in the following video:
https://www.youtube.com/shorts/9xhybDWOSxo