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May 11, 2009 - Circumpolar Sea of Sand

Circumpolar Sea of Sand  Much like the polar caps of Earth, which are surrounded by oceans, the north pole of Mars is surrounded by a sea of sand. This image, taken by the Mars Odyssey spacecraft, shows an ocean of dark sand dunes, covered in carbon dioxide frost, and sculpted by wind into long lines. The large sand deposits and the high speed winds that circulate around the pole allow for the formation of a huge dune field that surrounds the north polar cap. As the northern hemisphere progresses towards winter, carbon dioxide frost condenses out of the atmosphere and covers the dunes. During northern spring, the carbon dioxide sublimates and the dunes are once again uncovered and active. In this false-color image, cooler areas are in bluer tints, while warmer features are orange and yellow.

Image credit: NASA/JPL/ASU

Weekly Calendar

May 11-17, 2009

Holidays - Sky Events - Space History

Monday 11

1974: SMS-1 launched, first geostationary weather satellite
2009: STS-125 Atlantis launched, sixth and final Hubble Servicing mission

Tuesday 12

1930: Adler Planetarium opens, first planetarium in Western Hemisphere

Wednesday 13

Moon at apogee

1964: Apollo A-001 launched (Little Joe II test flight)

Thursday 14

1973: Skylab launched
2009: Herschel and Planck space observatories launched

Friday 15

1958: Sputnik 3 launched
1963: Faith 7 launched, last Mercury program flight
1997: STS-84 Atlantis launched, final Hubble servicing mission

Saturday 16

Sunday 17

Last Quarter Moon 3:26 am
Jupiter and Neptune 3° south of Moon

1836: Norman Lockyer born

Suggestions for new history dates or better links? Corrections for errors on this page? Please e-mail me.