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Earth and Moon, As Seen From Mars

Earth/Moon System seen from Mars. Credit: NASA/JPL/University of Arizona
This picture was released a couple of days ago, but since it’s so special, it deserves a post on Universe Today. And besides, everyone secretly likes to look at pictures of themselves. And this is a picture of us: it’s the Earth and the moon, as seen from Mars. From the Mars Reconnaissance Orbiter, to be exact, and it was taken by the HiRISE Instrument on board, the High Resolution Imaging Science Experiment. That’s the same camera that gave us the images of the avalanche on Mars, so the capabilities of this instrument are quite spectacular. This image was snapped back in October 2007, from a distance of 142 million kilometers, and if you look closely, you can make out a few features on Earth.

The west coast outline of South America is at lower right on Earth, although the clouds are the dominant features. In fact, the clouds were so bright, compared with the Moon, that they almost completely saturated the filters on the HiRISE camera. The people working on HiRISE say this image required a fair amount of processing to make a such a nice-looking picture. Yes, I agree, we are looking quite nice.

The phase angle is 98 degrees, which means that less than half of the disks of the Earth and Moon have direct illumination from the sun; that’s the reason we only see about half of each object. The scientists working on HiRISE say they would be able to image the Earth and moon when they are fully illuminated, but only when they are on the opposite side of the sun from Mars. However, then the distance would be much greater and the image would show less detail.

At this distance, this HiRISE image has a scale of 142 km/pixel, giving the Earth diameter about 90 pixels and the Moon diameter 24 pixels.

And now, back to the target that HiRISE was originally designed for: Mars. Here’s a very colorful (and false color) image that highlights the different minerals in Nili Fossae on Mars, one of the potential landing sites for the Mars Science Laboratory rover. From the CRISM instrument, the on-board spectrometer, scientists can discern that this area on Mars contains iron and magnesium, minerals that also contain water.
Nili Fossae on Mars.  Image Credit: NASA/JPL/University of Arizona

Original News Source: HiRISE Web page

About 

Nancy Atkinson is Universe Today's Senior Editor. She also works with Astronomy Cast, and is a NASA/JPL Solar System Ambassador.

Comments on this entry are closed.

  • Tom March 9, 2008, 10:45 AM

    Mauro, looks like you might be correct. I did a quick check of distances (per the CalSky website) and on 15 October 2007 Mars was at a distance of about 0.87 AU, or 130344160.2 km, which is about 80.992 million miles.

    Interesting.

  • Steve G March 9, 2008, 9:02 PM

    One would think that the Earth seen from Mars would be at least as bright as Mars is sen on Earth.

    The stars cannot be seen in this photo because they are much dimmer than the Earth or Moon. They are underexposed. If the camera were adjusted to see stars, the image of the earth would be overexposed.

  • Aseem March 9, 2008, 11:21 PM

    Hmm… I do not know about all the scientific and techy stuff about camera’s and exposures and distances betwn earth/sun/mars moon at particular date and time….
    but I showed this picture to everyone present today in my office (30 ppl) and EVERYONE thought that its a fake foto !!

    Once you put this pic. as ur wallpaper on desktop… (1280*1024) …it appears even more manipulated !….

    -Aseem
    (aschip@gmail)
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    Enough research tends to support whatever theory !

    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

  • sandeep November 9, 2008, 11:16 PM

    where are the stars…why always stars miss in each and every picture of NASA.

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