The Earth and Moon, as seen from Mars


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The Earth and Moon as seen from Mars

Cool image time! The image above, a composite of four separate Mars Reconnaissance Orbiter pictures, was taken on November 20, 2016.

Each was separately processed prior to combining them so that the moon is bright enough to see. The moon is much darker than Earth and would barely be visible at the same brightness scale as Earth. The combined view retains the correct sizes and positions of the two bodies relative to each other.

The reddish region on Earth is Australia, with Antarctica the bright white area below that.

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9 comments

  • eddie willers

    Just way too cool. Summertime in Antarctica.

  • BSJ

    If you use a program like Stellarium, you can change you location to Mars and then set it to view the Earth, as seen from Mars. Then plug in the date May 11, 1984 you can view a simulation of the Earth and the Moon transiting the Sun together.

    The Moon is TINY and very far from the Earth!

    The above image was taken when the Earth and Moon were close to the same alignment, as seen from the orbiter, or they cropped out a lot of ‘space’ between them.

    Still a view I’d like to see from my own telescope, from Mars!

  • BSJ: They admit that the Earth and Moon were taken in different images and then placed near each other, aligned correctly but much closer than they would be seen in real life. Read the link I provided.

  • LocalFluff

    I’ve never understood why the Moon is so bright white when seen from Earth, but so dark when imaged from space.

  • BSJ

    It doesn’t say that at all.

    “The combined view retains the correct sizes and positions of the two bodies relative to each other.”

    I just ran the simulation of the view through Stellarium for Nov. 20. and it shows that the Earth and Moon were in near alignment as seen from Mars. About 52″ of separation. Matching the image…

    The 1986 simulation had about 12′ of separation. The Earth had an apparent diameter of 32.7″ and the Moon 8.9″. The view is similar to what I saw in the most recent transits of Venus and Mercury, but combined.

  • BSJ: I stand corrected. And am actually thrilled to discover this is how the Earth and Moon actually appear from Mars. I had been under the impression that they are generally too far apart to get a photo of both at the same time.

  • wayne

    Question on these NASA pictures:

    Do they release the associated meta-data (or “EXIF” data) for these pictures?

    Even my little digital camera, produces all sorts of data on focal-length, shutter speed, ISO value, bit-depth, pixels, color balance, etc. It even tags the GPS coordinates if I have that function turned on.

    BSJ– good deal on the Stellarium software! Appreciate your leg-work.

  • BSJ

    Yeah, I should have run the Nov. 20 simulation before. Rather than just relying on memory of the 1968 transit image…

  • LocalFluff

    The Moon is about 30 Earth diameters away from Earth. But this image can have been taken when the Earth is between Mars and the Moon (since the Moon is a bit more than half lit). The Moon’s inclination is about 5 and Mars’ about 2 degrees. So the Moon being about two Earth diameters below Earth in the image, is reasonable given that its actual distance from Earth is 30 dE.

    Imagine that the Moon has only 1.2% of the Mass of Earth, it is a small little world! Still, moons don’t get larger than this. There’s a complicated explanation for the upper size limit of moons in the Solar system. When they formed out of the stuff in the protostellar disk, they spiraled into their gas giant. Many moons were destroyed that way. Jupiter’s moons were the ones that remained when the disk got thin enough for them to stay where they were. Stars with another density in their disk and their sized gas giants could form larger moons. Earth’s moon is a freak that doesn’t fit that theory, so a big unique collision is the accepted explanation. Just by chance it happens to have the same size as the other largest moons. Hmmm. Like Triton of Neptune which obviously was captured because it orbits the wrong way around. Hmmm. Well, one can’t have a Solar system for 4,567,000,000 years completely without coincidences. It would be unlikely to not have some unlikely outcomes.

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