* Astronomy

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RE: Mercury

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Images from NASA's Messenger spacecraft hint at the presence of solidified lava flows on the surface of Mercury. If confirmed, they should provide crucial clues to unlocking the planet's history.

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This is an image of the limb of Mercury taken by MESSENGER as it approached the planet from about 1 1/2 Earth diameters away.

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Credit: MESSENGER Teams, JHU APL, NASA

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Caloris Basin

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RE: Mercury

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A series of images taken between Jan. 9 and Jan. 13 as the Messenger spacecraft approached Mercury.
Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

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Average Distance From Sun:	58 Million KM
Nearest Distance to Earth:	85 Million KM
Temperature on Sunlit Side:	400°C
Temperature on Dark Side:	-170°C
Diameter:	4880 KM
Mass:	0.056 Earth Standard
Gravity:	0.38 Earth Standard
Atmosphere:	Traces of Helium, Neon, Argon
Moons:	None
Mercury Year:	88 Earth Days
Mercury Days:	59 Earth Days

Mercury

is the closest planet to the Sun.

In 1974 the US space probe Mariner 10 discovered that its surface is cratered by meteorite impacts. Its largest known feature is the Caloris Basin, 1,400 km, There are also cliffs hundreds of kilometres long and up to 4 km high, thought to have been formed by the cooling of the planet billions of years ago.
Inside is an iron core three-quarters of the planet's diameter, which produces a magnetic field 1% the strength of the Earth's.

to go to Transit page.

Being the closest planet to the sun, Mercury has to endure extremely high temperatures and any atmosphere there may have been, would have been burnt off long ago. A mystery is why has mercury still got a molten core, and magnetic field; it should have cooled down long ago.

Mercury

usually appears as a bright "star" with a yellowish or ochre hue. At its best evening apparitions, it can be found almost directly above where the Sun has set, being visible for up to 90 minutes after sundown.
During its best morning apparitions, you'll find it positioned almost directly above where the Sun will rise up to 90 minutes prior to sunrise.


	Click to Expand !

for large colourmap

for large bumpmap

for large photo of Mercury.

Currently,

a spacecraft called, MESSENGER, is on it`s way to visit Mercury.
The flybys will have approach phase angles of 112° (in October 2007) and 129° (July 2008). The angles correspond to the Sun lighting 1/3 and 1/5 of the surface facing MESSENGER as the spacecraft approaches.
MESSENGER can view opposite sides of the never-before-imaged hemisphere of Mercury soon after minimum altitude passage.

to read more.

During the Mercury flybys

MESSENGER will map nearly the entire planet in color, image most of the part of the planet unseen by Mariner 10, and take reconnaissance measurements of surface, atmosphere and magnetosphere composition. This would be a full science return for some missions, but it is just the start for MESSENGER. The flyby results will be invaluable for planning the yearlong orbital mission that follows.

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Mercury magnetic field

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RE: Mercury

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Title: A Side of Mercury Not Seen By Mariner 10
Authors: Gerald Cecil, Dmitry Rashkeev (University of North Carolina at Chapel Hill)

More than 60,000 images of Mercury were taken at ~29 deg elevation during two sunrises, at 820 nm, and through a 1.35 m diameter off-axis aperture on the SOAR telescope. The sharpest resolve 0.2" (140 km) and cover 190-300 deg longitude -- a swath unseen by the Mariner 10 spacecraft -- at complementary phase angles to previous ground-based optical imagery. Our view is comparable to that of the Moon through weak binoculars. Evident are the large crater Mozart shadowed on the terminator, fresh rayed craters, and other albedo features keyed to topography and radar reflectivity, including the putative huge ''Basin S'' on the limb. Classical bright feature Liguria resolves across the northwest boundary of the Caloris basin into a bright splotch centred on a sharp, 20 km diameter radar crater, and is the brightest feature within a prominent darker ''cap'' (Hermean feature Solitudo Phoenicis) that covers much of the northern hemisphere between longitudes 80-250 deg. The cap may result from space weathering that darkens via a magnetically enhanced flux of the solar wind, or that reddens low latitudes via high solar insolation.

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Montage of some previous maps of Mercury and our data, cylindrical equidistant projection. (a) Mariner 10 photo map at left, at right is a mosaic of Arecibo radar images with a few showing north-south Doppler ambiguities (Harmon et al. 2007); (b) An example Mariner far image blurred to our resolution at left, Ksanfomality (2004)'s combination of the Baumgardner et al. (2000) and Dantowitz et al. (2000) Mount Wilson images in the middle, and at right our SOAR data.

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