Archive

Archive for the ‘Mars Reconnaissance Orbiter’ Category

NASA Observations Point To ‘Dry Ice’ Snowfall On Mars

September 12, 2012 Leave a comment

NASA’s Mars Reconnaissance Orbiter data have given scientists the clearest evidence yet of carbon-dioxide snowfalls on Mars. This reveals the only known example of carbon-dioxide snow falling anywhere in our solar system.

Frozen carbon dioxide, better known as “dry ice,” requires temperatures of about minus 193 degrees Fahrenheit (minus 125 Celsius), which is much colder than needed for freezing water. Carbon-dioxide snow reminds scientists that although some parts of Mars may look quite Earth-like, the Red Planet is very different. The report is being published in the Journal of Geophysical Research.

“These are the first definitive detections of carbon-dioxide snow clouds,” said the report’s lead author, Paul Hayne of NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “We firmly establish the clouds are composed of carbon dioxide — flakes of Martian air — and they are thick enough to result in snowfall accumulation at the surface.”

Full Story: http://www.jpl.nasa.gov/news/news.php?release=2012-286

Advertisements

Mars’s Dramatic Climate Variations Are driven By The Sun

September 6, 2012 Leave a comment

Image Credit: NASA/JPL/UA

The ice caps on Mars’s poles are kilometres thick and composed of ice and dust. There are layers in the ice caps, which can be seen in cliffs and valley slopes and we have known about these layers for decades, since the first satellite images came back from Mars. The layers are believed to reflect past climate on Mars, in the same way that the Earth’s climate history can be read by analysing ice cores from the ice caps on Greenland and Antarctica.

Solar insolation on Mars has varied dramatically over time, mainly due to large variations in the tilt of Mars’s rotational axis (obliquity) and this led to dramatic climate variations on Mars. For years people have tried to link the solar insolation and layer formation by looking for signs of periodic sequences in the visible layers, which can be seen in the upper 500 meters. Periodic signals might be traceable back to known variations in the solar insolation on Mars, but so far it has been unclear whether one could find a correlation between variations in insolation and the layers.

“Here we have gone in a completely different direction. We have developed a model for how the layers are built up based on fundamental physical processes and it demonstrates a correlation between ice and dust accumulation and solar insolation, explains Christine Hvidberg, a researcher in ice physics at the Centre for Ice and Climate at the Niels Bohr Institute at the University of Copenhagen.

Full Story: http://www.nbi.ku.dk/english/news/news12/marss-dramatic-climate-variations-are-driven-by-the-sun/

Exhumed Rocks Reveal Mars Water Ran Deep


By studying rocks blasted out of impact craters, ESA’s Mars Express has found evidence that underground water persisted at depth for prolonged periods during the first billion years of the Red Planet’s existence.

Impact craters are natural windows into the history of planetary surfaces – the deeper the crater, the further back in time you can probe.

In addition, rocks blasted out during the impact offer a chance to study material that once lay hidden beneath the surface.

Full Story: http://www.esa.int/export/esaSC/SEMKT91VW3H_index_0.html

NASA Orbiter Catches Mars Sand Dunes in Motion

November 18, 2011 Leave a comment

Images from NASA’s Mars Reconnaissance Orbiter show sand dunes and ripples moving across the surface of Mars at dozens of locations and shifting up to several yards. These observations reveal the planet’s sandy surface is more dynamic than previously thought.

“Mars either has more gusts of wind than we knew about before, or the winds are capable of transporting more sand,” said Nathan Bridges, planetary scientist at the Johns Hopkins University’s Applied Physics Laboratory in Laurel, Md., and lead author of a paper on the finding published online in the journal Geology. “We used to think of the sand on Mars as relatively immobile, so these new observations are changing our whole perspective.”

While red dust is known to swirl all around Mars in storms and dust devils, the planet’s dark sand grains are larger and harder to move. Less than a decade ago, scientists thought the dunes and ripples on Mars either did not budge or moved too slowly for detection.

Full Story: http://www.jpl.nasa.gov/news/news.cfm?release=2011-358