Astronomy Picture of the Day
Posted By admin On March 24, 2011 @ 8:40 pm In Photo Essays | Comments Disabled
[1]
Martian Moon Phobos from Mars Express
Credit: G. Neukum [2] (FU Berlin [3]) et al., Mars Express [4], DLR [5], ESA [6]; Acknowledgement: Peter Masek
Explanation: Why is Phobos so dark? Phobos [7], the largest and innermost of two Martian moons, is the darkest moon in the entire Solar System [8]. Its unusual orbit and color indicate that it may be a captured asteroid [9] composed of a mixture of ice and dark rock. The above picture [10] of Phobos near the limb of Mars was captured [11] in November, 2010 by the robot spacecraft Mars Express [12] currently orbiting Mars. Phobos [13] is a heavily cratered and barren [14] moon, with its largest crater [15] located on the far side. From images like this, Phobos [16] has been determined to be covered by perhaps a meter of loose dust [17]. Phobos orbits [18] so close to Mars that from some places it would appear to rise and set twice a day, but from other places it would not be visible at all. Phobos [19]‘ orbit around Mars is continually decaying — it will likely break up [20] with pieces crashing to the Martian surface in about 50 million years.
Visit the NASA/JPL website to view more Astronomy Pictures of the Day [21]
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URL to article: http://www.berthoudrecorder.com/2011/03/24/astronomy-picture-of-the-day-42/
URLs in this post:
[1] Image: http://www.berthoudrecorder.com/wp-content/uploads/2011/03/phoboslimb_marsexpress_big.jpg
[2] G. Neukum: http://www.esa.int/esaSC/SEMGQOXLDMD_people_0_iv.html
[3] FU Berlin: http://www.fu-berlin.de/
[4] Mars Express: http://www.esa.int/export/SPECIALS/Mars_Express/SEMVQ95V9ED_0.html
[5] DLR: http://www.dlr.de/pf
[6] ESA: http://www.esa.int/
[7] Phobos: http://en.wikipedia.org/wiki/Phobos_%28moon%29
[8] Solar System: http://solarsystem.nasa.gov/planets/
[9] asteroid: http://bb.nightskylive.net/asterisk/viewtopic.php?f=24&t=18014
[10] above picture: http://www.unmannedspaceflight.com/index.php?showtopic=480&st=195&p=167059&#entry167059
[11] captured: http://www.planetary.org/blog/article/00002791/
[12] Mars Express: http://www.esa.int/SPECIALS/Mars_Express/SEMFU55V9ED_0.html
[13] Phobos: http://apod.nasa.gov/apod/ap080414.html
[14] barren: http://apod.nasa.gov/apod/ap031109.html
[15] largest crater: http://apod.nasa.gov/apod/ap080410.html
[16] Phobos: http://apod.nasa.gov/apod/ap061203.html
[17] loose dust: http://apod.nasa.gov/apod/ap980914.html
[18] orbits: http://www.youtube.com/watch?v=7rxqZcO-0uI
[19] Phobos: http://apod.nasa.gov/apod/ap990313.html
[20] break up: http://adsabs.harvard.edu/abs/2008AGUFM.P51C1423H
[21] Astronomy Pictures of the Day: http://antwrp.gsfc.nasa.gov/apod/
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