Martian Snowflakes

Graduate student Renyu Hu, Assistant Professor Kerri Cahoy, and Professor Maria Zuber have determined that Mars’ carbon dioxide ‘snowflakes’ are about the size of red blood cells.

In the dead of a Martian winter, clouds of snow blanket the Red Planet’s poles — but unlike our water-based snow, the particles on Mars are frozen crystals of carbon dioxide. Most of the Martian atmosphere is composed of carbon dioxide, and in the winter, the poles get so cold — cold enough to freeze alcohol — that the gas condenses, forming tiny particles of snow. 

Using radio occultation measurements from Mars Global Surveyor, data from the climate sounding instrument onboard the Mars Reconnaissance Orbiter, and detection of reflective clouds by the MGS Mars Orbiter Laser Altimeter, graduate student Renyu Hu, along with Professors Kerri Cahoy and Maria Zuber have been able to measure the size of CO2 condensates in the polar atmosphere. 

Read more at MIT News more

Researchers have determined the size of CO2 snow particles on Mars, depicted in this artist's rendering as a mist or fog that eventually settles to the surface as carbon dioxide snow. Image: NASA, Christine Daniloff/MIT News


Renyu Hu

Kerri Cahoy

Maria Zuber

Hu, R, K. Cahoy & M. Zuber (2012) Mars atmospheric CO2 condensation above the north and south poles as revealed by radio occultation, climate sounder, and laser ranging observations, Journal of Geophysical Research, Planets, doi: 10.1029/2012JE004087 (in press)

Sara Seager

Further press coverage:

Wired (June 22)

National Geographic (June 22)

KCBS [radio interview with Kerri Cahoy] (June 23)

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