Rover moonlights as astronomer, capturing partial eclipse

CAPE CANAVERAL: Nasa’s Mars rover, Curiosity, sent to determine if the planet most like Earth in the solar system could have supported microbial life, has taken on a second job – moonlighting as an astronomer.

Last week, Curiosity fitted protective filters to its highresolution camera and took pictures of the sun as Phobos, one of Mars’s two small moons, sailed by. Phobos and its sister moon, Deimos, are closer to Mars than our moon is to Earth, so they pass across the sky relatively quickly. Phobos takes less than eight hours to circle Mars. Deimos takes about 30 hours to do so. On Thursday last week, the moons started to cross paths.

“Phobos grazed the edge of the sun, as seen from Curiosity. We had basically a partial eclipse,” astronomer Mark Lemmon said.

The rover took more than 600 images with its left and right cameras, about 100 of which captured some part of the eclipse. From the other side of the planet, the rover Opportunity also photographed the eclipse on Wednesday.

The images should

help scientists learn more about Mars’s internal structure.

Like Earth’s moon, Mars’s moons have some gravitational pull that slightly change the planet’s shape. “That in turn changes the moons’ orbits – Phobos is slowing down, Deimos is speeding up,” Lemmon said.

In 10-15 million years, Phobos is expected to be so close to Mars it will be torn apart by the planet’s gravity. The pictures of the moons’ passages past the sun will help scientists assess how much they affect Mars’s shape.

The next Martian eclipses will take place in 11 months. By then, Curiosity should be at a better vantage point. Its eventual target is a 5km-high mound of sediment in the Gale Crater where it landed six weeks ago. – Reuters