Organic molecules on Mars
On 6 August 2012, the Sample Analysis at Mars (SAM) instrument suite (1) arrived on Mars onboard the Curiosity rover. SAM’s main aim was to search for organic molecules on the martian surface. On page 1096 of this issue, Eigenbrode et al. (2) report SAM data that provide conclusive evidence for the presence of organic compounds—thiophenic, aromatic, and aliphatic compounds—in drill samples from Mars’ Gale crater. In a related paper on page 1093, Webster et al. (3) report a strong seasonal variation in atmospheric methane, the simplest organic molecule, in the martian atmosphere. Both these finding are breakthroughs in astrobiology.
Since NASA’s Curiosity rover landed on Mars in 2012, it has sifted samples of soil and ground-up rock for signs of organic molecules—the complex carbon chains that on Earth form the building blocks of life. Past detections have been so faint that they could be just contamination. Now, samples taken from two different drill sites on an ancient lakebed have yielded complex organic macromolecules that look strikingly similar to kerogen, the goopy fossilized building blocks of oil and gas on Earth. At a few dozen parts per million, the detected levels are 100 times higher than previous finds, but scientists still cannot say whether they have origins in biology or geology. The discovery positions scientists to begin searching for direct evidence of past life on Mars and bolsters the case for returning rock samples from the planet, an effort that begins with the Mars 2020 rover.
2018-07-25
NASA Statement on Possible Subsurface Lake near Martian South Pole
Science
Scientists have found evidence of a ‘lake’ on Mars
New evidence shows the presence of a large body of water, almost like a “lake,” one mile beneath the icy surface of Mars, according to a study published in the journal Science. They used data from Mars Express. If confirmed, this would be the largest body of liquid water found on Mars so far.
Photo via @cnni
Far beneath the ice cap at Mars’s south pole lies a lake of liquid water—the first to be found on the Red Planet:
The view of Mars shown here was assembled from MOC daily global images obtained on May 12, 2003.
Credits: NASA/JPL/Malin Space Science Systems
A new paper published in Science this week suggests that liquid water may be sitting under a layer of ice at Mars’ south pole.
The finding is based on data from the European Mars Express spacecraft, obtained by a radar instrument called MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding). The Italian Space Agency (ASI) led the development of the MARSIS radar. NASA provided half of the instrument, with management of the U.S. portion led by the agency’s Jet Propulsion Laboratory in Pasadena, California.
The paper, authored by the Italian MARSIS team, outlines how a “bright spot” was detected in radar signals about 1 mile (about 1.5 kilometers) below the surface of the ice cap in the Planum Australe region. This strong radar reflection was interpreted by the study’s authors as liquid water — one of the most important ingredients for life in the Universe.
“The bright spot seen in the MARSIS data is an unusual feature and extremely intriguing,” said Jim Green, NASA’s chief scientist. “It definitely warrants further study. Additional lines of evidence should be pursued to test the interpretation.”
“We hope to use other instruments to study it further in the future,” Green added.
One of those instruments will be on Mars later this year. NASA’s InSight lander will include a heat probe that will burrow down as far as 16 feet (5 meters) below the Martian surface. The probe, built by the German Aerospace Center (DLR), will provide crucial data on how much heat escapes the planet and where liquid water could exist near its surface.
“Follow the Water” has been one of the major goals of NASA’s Mars program. Water is currently driving NASA’s exploration into the outer solar system, where ocean worlds — like Jupiter’s moon Europa and Saturn’s moon Enceladus — hold the potential to support life. Even protoplanets like Ceres may explain how water is stored in rocky “buckets” that transport water across the solar system.
Source : I
nge Loes ten Kate Department of Earth Sciences, Utrecht University, Utrecht, Netherlands:
i.l.tenkate@uu.nl in Science 08 Jun 2018: Vol. 360, Issue 6393, pp. 1068-1069
DOI: 10.1126/ science.aat2662
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