Explanation: What causes the black dots on dunes on Mars? As spring dawns on the Northern Hemisphere of Mars, dunes of sand near the poles being to defrost. Thinner regions of ice typically thaw first revealing sand whose darkness soaks in sunlight and accelerates the thaw. By summer, the spots will have expanded to encompass the entire dunes that will then be completely thawed and dark. The carbon dioxide and water ice actually sublimes in the thin atmosphere directly to gas. Taken in mid-July, the above image shows a field of spotted polar dunes spanning about 3 kilometers near the Martian North Pole. Meanwhile, in the Southern Hemisphere of Mars, the Earth-sent robot Martian rovers will try to survive through Martian winter, which peaks in mid-September.
1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 |
Yanvar' Fevral' Mart Aprel' Mai Iyun' Iyul' Avgust Sentyabr' Oktyabr' Noyabr' Dekabr' |
NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.
|
Publikacii s klyuchevymi slovami:
Mars - sand - Mars - peschanye dyuny
Publikacii so slovami: Mars - sand - Mars - peschanye dyuny | |
Sm. takzhe:
Vse publikacii na tu zhe temu >> | |
