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Space Science

Spirit Takes Snapshot of Earth 257

ControlFreal writes "On its 66th Sol on Mars, Mars Exploration Rover Spirit has obtained its first full view of crater Bonneville. In doing so, Spirit achieved its primary travel destination, as set out in its initial itinerary. Furthermore, Spirit has now travelled more than 300 meters, thereby fulfilling its minimum mission success criteria. With this, and Opportunity halfway through its primary mission, and having discovered very strong indications of a wet Martian past, NASA has truly many an astonishing interplanetary succes story! See the overview at the Mars Rover site for more details." Another reader writes "Among the 'money-shots' from the Mars rovers would have to rank the 'pale blue dot' image released today--a view looking back towards Earth. The larger image also includes the horizon and Sun, which because the Earth is seen as an inner planet closer in towards the Sun from a martian perspective, is difficult to photograph without saturation by solar glare."
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Spirit Takes Snapshot of Earth

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  • by the pickle ( 261584 ) on Friday March 12, 2004 @10:18AM (#8542678) Homepage
    So here's some cheap karma-whoring, a repost of the Astrobio.net article.

    You Are Here

    Earth as Viewed from the Martian Surface
    by Astrobiology Magazine staffwriter

    Consistently highly rated among those memorable 'money-shots' from the current Mars' surface exploration is a view looking back towards the Earth. On Thursday, the Spirit rover team released the banner image showing the Earth as a tiny gray dot in the martian sky near the horizon.

    The history of such views backwards towards the home planet, Terra Firma, have captivated the imagination for a generation of astronomers. This glimpse from the surface of another planet offers an unrivalled perspective that stretches beyond just seeing our home as one of many planets, or the only pale blue dot in our solar system.

    As Carl Sagan's widow, Anne Druyan , described this perspective image to Astrobiology Magazine, such earth views make "us look at this tiny planet, at the pale blue dot, and to see it in its real context, in its actual circumstances, in its true tininess. I don't know anyone who's able to really see that one-pixel Earth and not feel like they want to protect the Earth; that we have much more in common with each other than we're likely to have with anyone anywhere else."

    The evocative phrase describing the Earth as a 'pale blue dot' was coined by Carl Sagan after seeing our planet as a single pixel. The view was taken from the departing Voyager spacecraft. The entire earth could be encompassed as a flicker of light. The first image of Earth ever taken from another planet that actually shows our home as a planetary disk was captured by the Mars Orbital Camera on May 8th.

    One question that might be answerable from such a world-view is could a scientist on Mars identify from such a perspective that the Earth harbored life. In 1993, a team of researchers inspired by Carl Sagan, used an Earth fly-by of the Galileo spacecraft on its way to Jupiter to catch a glimpse of how the Earth might appear from afar. For astrobiologists, Sagan's results were surprising.

    Rather than seeing the Earth as an obvious candidate for life, the Galileo pictures gave surprisingly few clues of the biological potential of our own planet.

    From afar, how Galileo missed the obvious signs of terrestrial life as we would have expected to see them, was at first disconcerting to the scientific community, because future missions aim to observe more distant extrasolar planets and detect what would be visible in the spectra--the 'pale blue dot' scenario.

    One answer may lie in the fact that the spacecraft made its observations while still quite close to the Earth.

    "The spectrograph was designed to look at small areas of Jupiter, so the field of view of the spectrograph was quite small," said Nick Woolf of Arizona, in earlier discussions with the Astrobiology Magazine.

    "Also, since the surface brightness of Jupiter [the Gaileo's intended visual target] is far less than the Earth, the spectrograph detectors saturated except when the spectrograph was pointed at the darkest area of Earth - a cloud-free section of sea," Woolf noted. The cloud-free sea is considered very dark relative to the dominance of bright clouds in a global picture of Earth. Thus it should come as no surprise that Galileo was successful in only imaging a relatively dark and lifeless planet, mainly because its design was not intended to look at Earth, but to probe Jupiter instead.

    A spectroscope that might detect infrared or visible light looking back on Earth or outwards to other planets might focus mainly on four gases that are found in Earth's atmosphere and linked to life:
    • Water vapor - A baseline sign, indicating the presence of liquid water, a requirement of known life.
    • Carbon dioxide - Can be created by biological and non-biological processes. Because it is necessary for photosynthesis, it would indicate the possible presence of green plants.
    • Methane - Considered suggestive
  • Seriously... (Score:5, Informative)

    by Phidoux ( 705500 ) on Friday March 12, 2004 @10:28AM (#8542753) Homepage
    Sorry about the silly offtopic 1st post but I just couldn't resist.

    More seriously, I have been following the twin rover missions with great interest and I think it's absolutely amazing what they (And the JPL team of course) have achieved. I looked with great interest at the pic of our "pale blue (Even though the pic is monochrome) dot"

    Even on the relatively tiny (In relation to astronomical standards) scale of a view from our nearest neighbour, it is truly humbling to realise just how insignificant our rock, in the greater scheme of things, really is.

    Some of you might be interested in visiting a site that I visit on a daily basis to get and update on the latest images from Mars - photojournal.jpl.nasa.gov [nasa.gov]

  • by UltimaGuy ( 745333 ) on Friday March 12, 2004 @10:31AM (#8542770) Homepage
    Here is a link if the original site is /. http://linux.iconrate.net/gallery/11-ml-02-earth-A 067R1.jpg
  • Re:Shiny! (Score:5, Informative)

    by brownpau ( 639342 ) on Friday March 12, 2004 @10:46AM (#8542891) Homepage
    Shamelessy reposted with some edits from Metafilter... ....But what is that glint to the left side? [nasa.gov]

    I thought at first it was just a digital photo artifact, but seeing as how the flash of white appears in several photos from Spirit's navcam on Sol66 [nasa.gov], my next thought was ALIEN BUILDINGS!!!

    Okay, not really. My next thought was that it might be the lander's backshell or heatshield. So I looked up a map of the rover's intended route [nasa.gov], and orbital images of the landing site with labels [msss.com]. Take a look at the photos, the maps, and the scales. Apparently the lander's heatshield had impacted a nearby crater; that's Bonneville.
  • by Anonymous Coward on Friday March 12, 2004 @10:47AM (#8542904)
    Unfortunately if you look back at the Earth you're looking towards the sun.

    While the cameras are probably good enough, the Moon isn't well lit and there's a lot of glare. It doesn't surprise me that you can't make out the Moon (although it probably is in the photo).
  • Titan drop (Score:3, Informative)

    by Hayzeus ( 596826 ) on Friday March 12, 2004 @10:57AM (#8542997) Homepage
    The ESA has piggy-backed a probe (Huygens) onto Cassini, due to drop into Titan's surface around Jan/2005. Assuming it makes it to the surface, the expected lifetime of the probe will only be around 3 minutes or so (on the surface) but it will be relaying pictures back. For more info see:

    The Huygens mission page at NASA [nasa.gov]

  • by l0wland ( 463243 ) <<l0wland> <at> <yahoo.com>> on Friday March 12, 2004 @11:05AM (#8543055) Journal
    " The news coverage of the exciting explots of these plucky extra-terrestrial rovers seems to have diminished."

    When the press-conference of NASA was given about their revolutionairy findings, CNN was the only channel (at least here in The Netherlands) that paid attention to it. But as soon as it became clear that they had found indications for water, and NOT little green man, they immediately switched to other news. I think they only showed about 4 minutes of the press-conference. That shows how much (or lack of) interest the press and most of the public have in this mission. And I think it's sad, looking at the importance of it all.

  • by TrackerChamp ( 595492 ) on Friday March 12, 2004 @11:26AM (#8543224)
    Well, you could - for example - look at the photo of Earth and moon together [esa.int] that was taken from the European Mars Express half way enroute to Mars. You can clearly see Earth & moon as small spots in the universe. Very interesting photo, I think!
  • by Fedallah ( 25362 ) on Friday March 12, 2004 @11:57AM (#8543493) Homepage
    But from our nearest neighboring planet, we're just another dot in the sky.

    Make that second nearest neighboring planet. I knew something looked wrong with that statement. =)
  • Comment removed (Score:4, Informative)

    by account_deleted ( 4530225 ) on Friday March 12, 2004 @12:00PM (#8543515)
    Comment removed based on user account deletion
  • Re:hmmm (Score:4, Informative)

    by jxs2151 ( 554138 ) on Friday March 12, 2004 @12:40PM (#8543949)
    Mr Sagan probably said it better [planetary.org] than any of us can.
  • Re:Stars (Score:5, Informative)

    by Abcd1234 ( 188840 ) on Friday March 12, 2004 @01:07PM (#8544325) Homepage
    Somehow, I doubt it. Just a little perspective. Based on the current position of Earth and Mars:

    Distance from Earth to the closest star in Orion (HD 30652): 26.176 lightyears

    Distance from Earth to Mars: 0.0000278306 lightyears.

    So, the distance from Earth or Mars is 0.00010632% the distance from Earth to 30652.

    Basically, we're so damned far from Orion that, no matter where you were in the *solar system*, it would probably look the same.

    Incidentally, if you want to check this out for yourself (ie, look at the constellations from orbit around Mars), and you have a hardware-accelerated 3D card, I would highly recommend trying out Celestia [shatters.net], a very impressive space simulator
  • by Docrates ( 148350 ) on Friday March 12, 2004 @01:22PM (#8544506) Homepage
    And that quote, for the un-initiated, is from Hamlet. Made famous in the geek community because Picrad liked it.

    Oh you don't know who Picard is? Taco, remove his account, now!
  • Whoops! (Score:3, Informative)

    by LMCBoy ( 185365 ) on Friday March 12, 2004 @01:31PM (#8544603) Homepage Journal
    I forgot to convert from radians to degrees. The actual Earth-Moon separation as seen from Mars now is about 4 arcmin, not 4 arcsec. Still not resolvable in this wide-field image, but I thought that my trifling factor-of-60 error was worth a correction :)
  • by Anonymous Coward on Friday March 12, 2004 @02:00PM (#8544940)
    If you were a good nerd like me and followed the mission closely, you'd realize that it is the heat shield. They showed it way at the beginning of the mission from the MGS cameras, it was right at the edge of the crater

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