LOS ANGELES, April 4 (Xinhua) -- NASA's Curiosity rover has captured two solar eclipses on Mars over the past few weeks caused by Phobos and Deimos, Mars' two moons, according to a NASA release on Thursday.
Curiosity captured the eclipses by its Mast Camera (Mastcam), and sent some spectacular imagery back to the earth.
Phobos, which is about 11.5 kilometers across, was imaged on March 26, 2019. Deimos, which is about 2.3 kilometers across, was photographed on March 17, 2019.
According to NASA, Phobos doesn't completely cover the sun, so it would be considered an annular eclipse. As Deimos is so small compared to the disk of the sun, scientists said it's "transiting" the sun.
In addition to capturing each moon crossing in front of the sun, one of Curiosity's Navigation Cameras (Navcams) observed the shadow of Phobos on March 25, 2019. As the moon's shadow passed over the rover during sunset, it momentarily darkened the light.
Solar eclipses have been seen many times by Curiosity and other rovers in the past. These events helped researchers fine-tune their understanding of each moon's orbit around Mars.
Mark Lemmon, a co-investigator with Curiosity's Mastcam, said before the Spirit and Opportunity rovers landed in 2004 that there was much higher uncertainty in the orbit of each moon. The first time one of the rovers tried to image Deimos eclipsing the sun, scientists found the moon was 40 kilometers away from where they expected.
"More observations over time help pin down the details of each orbit," Lemmon said. "Those orbits change all the time in response to the gravitational pull of Mars, Jupiter or even each Martian moon pulling on the other."
Eclipses, sunrises and sunsets and weather phenomena all make Mars real to people, as a world both like and unlike what they see outside, not just a subject in a book, Lemmon said.
To date, there have been eight observations of Deimos and about 40 observations of Phobos eclipsing the sun from either Spirit, Opportunity or Curiosity rover, according to NASA.