Published on February 7th, 20140
How is Earth seen from Mars? Curiosity has “photographed” Earth
Using images taken by the rover Curiosity Mastcam instrument in the 529 th day of its mission to Mars, experts have obtained photos of planet Earth, which appears as a small “star” that lights the Martian night sky.
In the 529 th day of its mission to Mars, Curiosity turned his “look” into the sky to the west, capturing the image of the Earth over the edge of the Gale crater, where the mission of the Mars rover took place.
It took meticulous analysis and image processing to identify Earth through the luminous formations that appear in images. Analyzing more pictures taken by the rover instruments and processing them using a software called Stellarium, scientists have managed to realize that one of the bright spots that appear in the sky is actually Earth.
An advanced processing allowed to designate another bright spot as the Moon, sown by the pictures below. The experts think there are Earth and its natural satellite.
Let’s do the math. A look at our solar system simulator shows that the Moon was very near the Earth by the time of the observation — 360,000 kilometers from Earth. At the same time, Earth is relatively far away from Mars, about 159 million kilometers. So Earth and the Moon were separated by about (360k/159000k)=2.3 milliradians. The angular resolution of the Mastcam-100 is 0.074 milliradians. So they should be separated by 30 pixels. I measured 25. Could be the Moon, though the math didn’t work out quite as close as we would have liked it to. This animation is less pretty than the one above, because the Moon (if that’s what it is) is a much, much dimmer target than Earth, so it’s nearly lost among the noise and JPEG compression. A better version can be made from the science data once it becomes available.