Nov 27, 2022 I Paul Seaburn

Rover Finds Possible Organic Compounds on Mars as SHERLOC Homes in on Life Signs

While the space-watching world (at least in the U.S.) has its eyes pointing to the Moon and the Orion spacecraft making a trip that lays the groundwork for the return of humans to the lunar surface, the Perseverance rover on Mars is slowly roving its way to what may be the biggest announcement in history – the discovery of life on Mars. Researchers from Caltech and Imperial College London announced this week that the SHERLOC instrument on the rover’s arm had homed in on rocks on the floor of the Jezero crater and found evidence of liquid water and signatures that could be organic compounds … the potential building blocks of life. What would David Bowie say?

Is there life on MArs?

“It's a God-awful small affair.”

(from “Life on Mars” by David Bowie)

David Bowie would be frustratingly right with that assessment of the announcement published this week in the journal Science. As the title “Aqueous alteration processes in Jezero crater, Mars−implications for organic geochemistry” implies, the SHERLOC (Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals) instrument has made small but nonetheless extremely significant progress in the search for signs of past life on Mars.  SHERLOC, like its namesake inspiration, is a multi-faceted detective – its tools include a Raman spectrometer, which utilizes a NeCu laser to generate UV photons which can generate characteristic Raman and fluorescence photons from a Martian surface sample to identify organic compounds. Upon finding possible signatures, it can also map how they are distributed within the sample and potentially determine what led up to them being preserved in that specific location.

“We identify evidence for two distinct ancient aqueous environments at different times.”

Perseverance found three rocks in the Jezero delta area of the crater worth examining with SHERLOC and the fluorescence detective determined they were from different places and different times. The delta was chosen because, like on Earth, they form at the mouth of a river as its fast-moving waters carrying sediments and small rocks from far away locales meet a lake or other still body of water that slows it down and forces the deposits to drop to the bed and build up over time. Any life forms – from large aquatic creatures to microorganisms – will fall to the bottom as well and their fossils will remain there for eons until the waters recede and they are exposed to the elements … and the rovers, probes and eventually humans sent from Earth. Perseverance can’t wait for humans or retrieval landers, so it analyzed these delta rocks with SHERLOC and discovered a shocking surprise … something besides sedimentary rocks.

“In lake beds, the researchers expected to find sedimentary rocks, because the water deposits layer after layer of sediment. However, when the rover touched down there, some researchers were surprised to find igneous rocks (cooled magma) on the crater floor with minerals in them that recorded not just igneous processes but significant contact with water.

These minerals, such as carbonates and salts, require water to circulate in the igneous rocks, carving out niches and depositing dissolved minerals in different areas like voids and cracks. In some places, the data show evidence for organics within these potentially habitable niches.”

A detective’s job is to detect and that is exactly what SHERLOC did – the press release explains it detected evidence which eventually confirmed that these rocks were from “two distinct ancient aqueous environments at different times.” The analysis tool in SHERLOC found carbonates which were formed by reactions with liquid water in an olivine-filled (olivine is a magnesium-rich igneous rock believed to be the most abundant constituent of the Earth's upper mantle) igneous rock. A sulfate-perchlorate mixture also found in rocks indicates the rocks were affected later by salty brinish water. The biggest find was that the fluorescence analyzer in SHERLOC found signatures consistent with aromatic organic compounds preserved in minerals in the rocks from both aqueous environments. ‘Aromatic organic compounds’ are hydrocarbons that consist exclusively of the elements carbon and hydrogen and are keys to life on Earth – benzene and toluene are two common examples.

“The microscopic compositional imaging capabilities of SHERLOC have really blown open our ability to decipher the time-ordering of Mars’s past environments.”

Since the aromatic organic compounds are ‘god-awful small affairs’ that are close but not quite definitive proof that life once existed on Mars, Bethany Ehlmann, a co-author of the paper and  professor of planetary science, and associate director of the Keck Institute for Space Studies, tries to put a positive spin on what is still a significant discovery – signatures from different places and time periods that show life could have existed on Mars in different eras and areas. That is pretty significant when one considers the digging, scooping, imaging and analyzing was done by a tool on the arm of a rover millions of miles away in a hostile environment. That is pretty big … yet still just a small piece of the entire project which entails sending more probes to the Red Planet that will locate Perseverance, land near it, retrieve the rocks from its holding chamber, blast off and return them to Earth for human engineers (“Sherlocks”) to do more detective work on them in “laboratories with advanced instrumentation in order to determine definitively the presence and type of organics and whether they have anything to do with life.”

“Is there life on Mars?”

(from “Life on Mars” by David Bowie)

Why can't we find a sign like this?

Wherever he is now, David Bowie may know the answer to his question … but we don’t yet. Those who think NASA, ESA and other space programs should be focusing on putting humans on Mars are missing just how much is being accomplished by the rovers and landers already there – on missions that have already proven that ‘robots’ can accomplish much while surviving in environments that are hostile, dangerous and potentially toxic to humans. There is sadness as the Mars InSight Lander is finally shutting down because the dust on its solar panels prevents its batteries from charging, but that is nothing compared to the reaction an astronaut’s death would generate, and the negative impact it would have on future human missions to the Moon, Mars and beyond.

Perhaps David Bowie was right … Perseverance is the best-selling show and the one we should be asking. Wonder if it will ever know?

Oh man, wonder if he'll ever know

He's in the best selling show

Is there life on Mars?

(from “Life on Mars” by David Bowie)

Paul Seaburn

Paul Seaburn is the editor at Mysterious Universe and its most prolific writer. He’s written for TV shows such as "The Tonight Show", "Politically Incorrect" and an award-winning children’s program. He's been published in “The New York Times" and "Huffington Post” and has co-authored numerous collections of trivia, puzzles and humor. His “What in the World!” podcast is a fun look at the latest weird and paranormal news, strange sports stories and odd trivia. Paul likes to add a bit of humor to each MU post he crafts. After all, the mysterious doesn't always have to be serious.

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