Latest about what Rover found on Mars

 Non-Life Explanations about what Rover found on Mars by NASA

Last year, NASA’s Curiosity rover made a fascinating discovery after boring into a suspected ancient lake bed on Mars: long-chain organic molecules, called alkanes, which could serve as a potential chemical relic of ancient life on the Red Planet. The molecules, researchers suggested at the time, could have derived from fatty acids, which are common building blocks of cell membranes on Earth, once again strengthening the case that Mars could’ve been teeming with life billions of years ago. It was just another tantalizing clue in our search for extraterrestrial life, not the smoking gun we’ve all been waiting for. At that time scientists studying a rock sample collected by NASA’s Curiosity rover disclosed something tantalizing: the largest organic molecules ever detected on Mars. The compounds, decane, undecane, and dodecane, may be fragments of fatty acids, which on Earth are most often linked to life. While non-living processes like meteorite impacts can also create such molecules, researchers found those sources couldn’t fully explain the amounts detected.

Nonetheless, scientists continue to be fascinated by the finding. A team led by NASA Goddard Space Flight Center’s Alexander Pavlov argues that the presence of these molecules, despite the millions of years of destructive radiation that pummeled the Martian surface after it lost much of its atmosphere,  “cannot be readily explained” by non-biological processes alone. One theory is that carbon-rich dust particles and meteorites could have deposited these long-chain organic molecules on the surface, with the ancient Martian atmosphere allowing the organics to accumulate billions of years ago. NASA's Curiosity Mars rover took a selfie at a location nicknamed Mary Anning after a 19th-century English paleontologist. Curiosity snagged three samples of drilled rock at this site on its way out of the Glen Torridon region. A new scientific analysis suggests that known non biological processes cannot fully explain the amount of organic material discovered in a rock collected on Mars by NASA's Curiosity rover. Organic compounds are carbon containing molecules that form the chemical building blocks of life as we know it. They can be created by living organisms, but some can also form through natural chemical reactions that do not involve life. Curiosity, which has been exploring Gale Crater since 2012, carries a miniature chemistry lab designed to heat rock samples and analyze the gases they release. Using this onboard laboratory, scientists detected several intriguing compounds in a drilled rock sample.

Nonetheless, scientists stopped well short of making any definitive statements about life on the Red Planet. After all, there could be still-unknown, non-biological processes we don’t know about that could have resulted in the observed concentration of long-chain carbon molecules on Mars. “We agree with Carl Sagan’s claim that extraordinary claims require extraordinary evidence and understand that any purported detection of life on Mars will necessarily be met with intense scrutiny,” they concluded. “In addition, in practice with established norms in the field of astrobiology, we note that the certainty of a life detection beyond Earth will require multiple lines of evidence.” Curiosity's instruments can identify molecules, but they cannot directly determine how those molecules formed. Because of this limitation, researchers could not tell whether the compounds were produced by biological activity or by non living chemical processes. To explore that question, scientists conducted a follow up investigation focused on known non biological sources. One possibility is that meteorites striking Mars delivered organic material to the surface. Meteorites are known to contain carbon based molecules, and impacts have been common throughout Martian history. The team evaluated whether this type of external delivery, along with other abiotic chemical reactions, could account for the levels of organic compounds measured in the sample.

The researchers reported that the non biological mechanisms they examined could not fully account for the abundance of organic compounds detected by Curiosity. Based on their analysis, they concluded that it is reasonable to consider the possibility that living organisms could have contributed to the formation of these molecules. This does not mean life has been confirmed on Mars. Instead, it suggests that non living explanations alone may not be sufficient to explain the data. However, Pavlov and his colleagues aren’t convinced. After studying how 80 million years’ worth of pelting radiation could have affected these molecules, they concluded that prior to the loss of the planet’s atmosphere, the concentration of these alkanes was likely much higher than previously thought. To help explain their findings, they took into account other non-biological processes in an attempt to arrive at their inferred original abundance,  but couldn’t, even after combining all of them. In other words, biological processes like the ones observed on Earth are still a leading theory, even after researchers’ best efforts to find a non-life explanation. “We argue that such high concentrations of long-chain alkanes are inconsistent with a few known abiotic sources of organic molecules on ancient Mars,” they said.

Earlier, researchers announced they had identified trace amounts of decane, undecane, and dodecane. These are hydrocarbons, meaning they are made only of carbon and hydrogen atoms. They belong to a group of molecules that can be related to fatty acids. Fatty acids are important components of cell membranes in living organisms on Earth, although similar molecules can also form through purely geological reactions under certain conditions. The rock that contained these compounds is an ancient mudstone located in Gale Crater. Mudstone forms from fine grained sediment that once settled in water, suggesting the area may have hosted lakes billions of years ago. Scientists proposed that the molecules detected by Curiosity could be fragments of fatty acids that were preserved in the rock over vast stretches of time. Nonetheless, it’s a tantalizing waypoint in our longstanding efforts to determine whether Mars, a planet that was once covered in huge oceans, rivers and lakes, could have supported life. Pavlov and his colleagues are now calling for further research into how radiation degraded these intriguing molecules under Mars-like conditions to shed more light on the matter.

To better understand how much organic material may have originally been present, the scientists combined laboratory radiation experiments, computer simulations, and Curiosity's measurements. Mars lacks a thick atmosphere and a global magnetic field like Earth's, which means its surface is constantly exposed to cosmic radiation. Over time, this radiation can break apart complex molecules. The team attempted to "rewind the clock" by about 80 million years, which is how long the rock is estimated to have been exposed at the Martian surface. By modeling how radiation gradually destroys organic molecules, they calculated how much material would have existed before being degraded. Their results indicate that the original quantity of organic compounds was likely far greater than what typical non biological processes are known to produce. The researchers emphasize that further experiments are necessary to understand how quickly organic molecules break down in Mars like rocks under Mars like environmental conditions. Laboratory studies that better replicate Martian temperatures, radiation levels, and chemistry will help refine these estimates. Until more data are available, scientists cannot draw firm conclusions about whether these compounds point to past life or can ultimately be explained through chemistry alone. What the findings do show is that the chemical story preserved in Martian rocks may be more complex and more intriguing than previously thought.