[meteorite-list] Latest MESSENGER Images Show Fascinating Views of Mercur...

Tue Jan 22 18:36:28 EST 2008

Tom:

There will be an article by Melinda Hutson on this very subject (meteorite
from Mercury) in either the February or May issue of Meteorite.

Larry

On Tue, January 22, 2008 4:26 pm, STARSANDSCOPES at aol.com wrote:
> Hi,  Thanks for the post.  I had to  remember to breath!
>
>
> Dr. Love had said there is a chance that meteorites  from Mercury are
> already in some collections.  What is the current view of  Mercurian
> Meteorites on
> Earth.
>
>
> Thanks,  Tom
>
>
> In a message  dated 1/22/2008 4:53:15 P.M. Central Standard Time,
> baalke at zagami.jpl.nasa.gov  writes:
>
> http://messenger.jhuapl.edu/news_room/status_report_01_20_08.html
>
>
> MESSENGER  Mission News
> January 20,  2008
>
>
> ------------------------------------------------------------------------
> Latest  MESSENGER Images Show Fascinating Views of Mercury's  Surface
> ------------------------------------------------------------------------
>
>
> MESSENGER  Views an Intriguing Crater
>
>
> MESSENGER's Narrow Angle Camera (NAC) on the  Mercury Dual Imaging System
>  (MDIS) acquired this  view
> <http://messenger.jhuapl.edu/gallery/sciencePhotos/image.php?gallery_id=2&
> imag e_id=127> of  Mercury's surface illuminated obliquely from the right
> by the Sun. The  unnamed crater (52 kilometers, or 31 miles, in diameter)
> in the center of the  image displays a telephone-shaped collapse feature
> on its floor. Such a  collapse feature, not seen on the floors of other
> craters in this image,  could reflect past volcanic activity at and just
> below the surface of this  particular crater.
>
> MESSENGER team members are examining closely the more  than 1,200 images
> returned from this flyby for other surface features that  can provide clues
> to the geological history of the innermost  planet.
>
> The crater is located in the southern hemisphere of Mercury, on  the side
>  that was not viewed by Mariner 10 during any of its three flybys in
> 1974
> and 1975. This scene was imaged while MESSENGER was departing  from Mercury
> from a distance of about 19,300 kilometers (12,000 miles),  about one hour
> after the spacecraft's closest encounter with Mercury.  The image is of a
> region approximately 236 kilometers (147 miles)  across, and craters as
> small as 1.6 kilometers (1 mile) can be  seen.
>
> ------------------------------------------------------------------------
>
>
> Ridges  and Cliffs on Mercury's Surface
>
>
> A complex history of geological evolution  is recorded in this  frame
> <http://messenger.jhuapl.edu/gallery/sciencePhotos/image.php?gallery_id=2&
> imag e_id=128> from  the Narrow Angle Camera (NAC), part of the MDIS
> instrument, taken during  MESSENGER's close flyby of Mercury on January
> 14, 2008. Part of
> an old, large  crater occupies most of the lower left portion of the frame.
> An arrangement  of ridges and cliffs in the shape of a "Y" crosses
> the crater's floor. The  shadows defining the ridges are cast on the floor
> of the crater by the Sun  shining from the right, indicating a descending
> stair-step of  plains.
>
> The main, right-hand branch of the "Y" crosses the crater floor,  the
> crater rim, and continues off the top edge of the picture; it appears  to
> be a classic "lobate scarp" (irregularly shaped cliff) common in  all
> areas of Mercury imaged so far. These lobate scarps were formed during  a
>  period when Mercury's crust was contracting as the planet cooled.  In
> contrast, the branch of the Y to the left ends at the crater rim and  is
> restricted to the floor of the crater. Both it and the  lighter-colored
> ridge that extends downward from it resemble "wrinkle ridges"  that are
> common on the large volcanic plains, or "maria," on the  Moon.
>
> The MESSENGER science team is studying what features like these  reveal
> about the interior cooling history of Mercury.
>
> Ghostly remnants  of a few craters are seen on the right side of this
> image, possibly  indicating that once-pristine, bowl-shaped craters (like
> those on the large  crater's floor) have been subsequently flooded by
> volcanism or some other  plains-forming process.
>
> This image was taken 18 minutes after close  approach, when MESSENGER was
>  about 5,000 kilometers (about 3,000 miles) away  from Mercury. The image
>  is about 200 kilometers (about 125 miles) across, and  features as small
>  as about 400 meters (about 400 yards) can be  resolved.
>
> ------------------------------------------------------------------------
>
>
> Additional  information and features from MESSENGER's first flyby of
> Mercury are online  at  http://messenger.jhuapl.edu/mer_flyby1.html.
>
>
> ------------------------------------------------------------------------
>
>
> MESSENGER  (MErcury Surface, Space ENvironment, GEochemistry, and
> Ranging) is a  NASA-sponsored scientific investigation of the planet
> Mercury and the first  space mission designed to orbit the planet closest
> to the Sun. The MESSENGER  spacecraft launched on August 3, 2004, and after
> flybys of Earth, Venus, and  Mercury will start a yearlong study of its
> target planet in March 2011. Dr.  Sean C. Solomon, of the Carnegie
> Institution of Washington, leads the mission  as principal investigator.
> The Johns Hopkins University Applied Physics  Laboratory built and
> operates the MESSENGER spacecraft and manages this  Discovery -class
> mission for  NASA.
>
>
>
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