I’ve long maintained that we’ll find compelling biosignatures on an exoplanet sooner than we’ll find them in our own Solar System. But I’d love to be proven wrong. The recent flurry of news over the interesting findings from the Perseverance rover on Mars is somewhat reminiscent of the Clinton-era enthusiasm for the Martian meteorite ALH8001. Now there are signs, as Alex Tolley explains below, that this new work will prove just as controversial. Biosignatures will likely be suggestive rather than definitive, but Mars is a place we can get to, as our rovers prove. Will Perseverance compel the sample return mission that may be necessary to make the definitive call on life?
by Alex Tolley
Overview of jezero Crater and sample site in article. Credit NASA/MSSS/USGS.
On September 10, 2025, Nature published an article that got wide attention. The authors claimed that they had discovered a possible biosignature on Mars. If confirmed, they would have won the race to find the first extraterrestrial biosignature. Exciting!
One major advantage of detecting a biosignature in our system is that we can access samples and therefore glean far more information than we can using spectroscopic data from an exoplanet. This will also reduce the ambiguity of simpler atmospheric gas analyses that are all we can do with our telescopes at present.
Figure 1. Perseverance’s path through Neretva Vallis and views of the Bright Angel formation. a, Orbital context image with the rover traverse overlain in white. White line and arrows show the direction of the rover traverse from the southern contact between the Margin Unit and Neretva Vallis to the Bright Angel outcrop area and then to the Masonic Temple outcrop area. Labelled orange triangles show the locations of proximity science targets discussed in the text. b, Mastcam-Z 360° image mosaic looking at the contact between the light-toned Bright Angel Formation (foreground) and the topographically higher-standing Margin Unit from within the Neretva Vallis channel. This mosaic was collected on sol 1178 from the location of the Walhalla Glades target before abrasion. Upslope, about 110 m distant, the approximate location of the Beaver Falls workspace (containing the targets Cheyava Falls, Apollo Temple and Steamboat Mountain and the Sapphire Canyon sample) is shown. Downslope, about 50 m distant, the approximate location of the target Grapevine Canyon is also shown. In the distance, at the southern side of Neretva Vallis, the Masonic Temple outcrop area is just visible. Mastcam-Z enhanced colour RGB cylindrical projection mosaic from sol 1178, sequence IDs zcam09219 and zcam09220, acquired at 63-mm focal length. A flyover of this area is available at https://www.youtube.com/watch?v=5FAYABW-c_Q. Scale bars (white), 100 m (a), 50 m (b, top) and 50 cm (b, bottom left). Credit: NASA/JPL-Caltech/ASU/MSSS.
Let’s back up for context. The various rover missions to Mars have proceeded to determine the history of Mars. From the Pathfinder mission starting in 1996, the first mission since the two 1976 Viking landers, the various rovers from Soujourner (1997), Spirit & Opportunity (2004), Curiosity (2012), and now Perseverance (2021), have increased the scope of their travels and instrument capabilities. NASA’s Perseverance rover was designed to characterize environments and look for signs of life in Jezero Crater, a site that was expected to be a likely place for life to have existed during the early, wet phase of a young Mars. The crater was believed to be a lake, fed by water running into it from what is now Neretva Vallis, and signs of a delta where the ancient river fed into the crater lake are clear from the high-resolution orbital images. Perseverance has been taking a scenic tour of the crater, making stops at various points of interest and taking samples. If there were life on Mars, this site would have both flowing water and a lake, with sediments that create a variety of habitats suitable for prokaryotic life, like the contemporary Earth.
Perseverance had taken images and samples of a sedimentary rock formation, which they called Bright Angel. The work involved using the Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) instrument to obtain a Raman UV spectrum of rock material from several samples. The authors claimed that they had detected 2 reduced iron minerals, greigite and vivianite, and organic carbon. The claim is that these have been observed in alkaline environments on Earth due to bacteria, and therefore prove to be a biosignature of fossil life. The images showed spots (figure 2) which could possibly be the minerals formed by the metabolism of anaerobic bacteria, reducing sulfur and iron for energy. The organic carbon in the mudstone rock matrix is the fossil remains of the bacteria living in the sediments.
Exciting, no? Possible proof that life once existed on Mars. The authors submitted a paper to Nature with the title, “Detection of a Potential Biosignature by the Perseverance Rover on Mars“. The title was clearly meant to catch the scientific and popular attention. At last, NASA’s “Follow the Water” strategy and exploration with their last rover equipped to detect biosignatures had found evidence of fossil life on Mars. It might also be a welcome boost for NASA’s science missions, currently under funding pressure from Congress.
Then the peer review started, and the story seemed less strong. Just as 30 years ago, when the announcement from the White House by the US president, Bill Clinton claimed that a Martian meteorite retrieved from the Antarctic, ALH8001, was evidence of life on Mars proved very controversial. Notably, slices of that meteorite viewed under an electron microscope showed images of what might have been some forms of bacteria. These images were seen around the world and were much discussed. The consensus was that the evidence was not unambiguous, with even the apparent “fossil bacteria” being explained as natural mineral structures.
Well, the new paper created one of the longest peer review documents I have ever read. Every claimed measurement and analysis was questioned, including the interpretation. The result was that the paper was published as the much drier “Redox-driven mineral and organic associations in Jezero Crater, Mars”. There are just 3 uses of the term biosignatures, each prefaced with the term “potential”, and the null hypothesis of abiotic origin emphasized as well. One of the three peer reviewers even wanted Nature to reject the paper, based on what might be another ALH8001 fiasco. A demand, too far.
What were the important potential biosignature findings?
Organisms extract energy from molecules via electron transfer. This often results in the compounds becoming more reduced. For example, sulfur-reducing bacteria convert sulfates (SO4) to sulfide (S). Iron may be reduced from its ferric (Fe3+) state to its ferrous (Fe2+) state. Two minerals that are often found reduced as a result of bacterial energy extraction are greigite Fe2+Fe3+2S4] and vivianite [Fe2+3(PO4)2·8H2O]. On Earth, these are regarded as biosignatures. In addition, unidentified carbon compounds were associated with these 2 minerals. The minerals were noticed as spots on the outcrop and identified with the Planetary Instrument for X-ray Lithochemistry (PIXL), which can identify elements via X-ray spectroscopy. The SHERLOC instrument identified the presence of carbon in association with these minerals.
Figure 2. An image of the rock named “Cheyava Falls” in the “Bright Angel formation” in Jezero crater, Mars, collected by the WATSON camera onboard the Mars 2020 Perseverance rover. The image shows a rust-colored, organic matter in the sedimentary mudstone sandwiched between bright white layers of another composition. The small dark blue/green to black colored nodules and ring-shaped reaction fronts that have dark rims and bleached interiors are proposed to be potential biosignatures. Credit: NASA/JPL-Caltech/MSSS.
To determine whether the carbon associated with the greigite and vivianite was organic or inorganic, the material was subjected to ultraviolet rays. Organic carbon bonds, especially carbon-carbon bonds, will respond to specific wavelengths by vibrating, like sound frequencies can resonate and break wine glasses. Raman spectroscopy is the technique used to detect the resonant vibrations of types of carbon bonds, particularly specific arrangements of the atoms and their bonds that are common in organic carbon. The spectroscopic data indicated that the carbon material was organic, and therefore possibly from decayed organisms. This would tie together the findings of the carbon and the 2 minerals as a composite biosignature. However, the reviewers also questioned the interpretation of the Raman spectrum.. The sp2 carbon bonds (120 degrees) seen in aromatic 6-carbon rings, in graphene, graphite, and commonly in biotic compounds, should show both a G-band (around 1600 cm-1) and a D-band (around 2700 cm-1), yet the spectrum only clearly showed the G-band. Did this imply that the organic carbon may not have been found? The reviewers also questioned why the biological explanation was favored over an abiotic one. No one questioned the greigite and vivianite findings, other than that they are not exclusively associated with anaerobic bacterial metabolism.
Figure 3 – Raman spectrum with interpolated curves to highlight the G-band in the 4 samples taken at the location.
So what to make of this? Clearly, the authors backed down on their more positive interpretation of their findings as a biosignature.
What analyses would we want to do on Earth?
Assuming the samples from Perseverance are eventually retrieved and returned to Earth, what further analysis would we want to do to increase our belief that a biosignature was discovered?
A key analysis would be to analyze the carbon deposits. The Raman UV spectra indicate that the carbon is organic, which is almost a given. You may recall that the private MorningStar mission to Venus will do a similar analysis but use a laser-induced fluorescence that detects aromatic rings [1]. Neither of these techniques can distinguish between abiotic and biogenic carbon. The carbon may even be in the form of common polycyclic aromatic hydrocarbons (PAH), a form that is ubiquitous and is easily formed, especially with heat.
One useful approach to distinguish the source of the carbon is to measure the isotopic ratios of the 2 stable carbon isotopes, carbon-12 and carbon-13. Living organisms favor the lighter carbon-12, and therefore, the C13/C12 ratio is reduced when the carbon is from living organisms. This must be compared to known abiotic carbon to confirm its source. This analysis requires a mass spectrometer, which was not included with the Perseverance instrument pack.
The second approach is to analyze the carbon compounds. Gas chromatography followed by infrared spectroscopy is used to characterize the compounds. Life restricts the variety of compounds compared to random reactions, and can be compared to expectations based on Assembly Theory [2], although exposure to UV and particle radiation for billions of years may make the composition of the carbon more random.
Lastly, if the carbon were once protein or nucleotide macromolecules, any chirality might distinguish its source as biotic.
Isotopic analysis can also be made on the sulfur compounds in the greigite. As with carbon, life will preferentially use lighter isotopes. Bacteria reduce sulfate to sulfide for energy, and the iron sulfide mineral, greigite, is a waste product of this metabolism. Of the 2 stable sulfur isotopes, sulfur-32 and sulfur-34, if the S34/S32 ratio is reduced, then this hints that the greigite was formed biotically.
Lastly, opening up the samples and inspecting them with an electron microscope, there may be physical signs of bacteria. However, any physical features will need to be identified unambiguously to avoid the ALH8001 controversy.
Unfortunately for these proposed analyses, the Mars Sample Return (MSR) mission has been cut with the much-reduced NASA budget. When, or whether, we get these samples for analyses on Earth is currently unknown.
My view on the findings
If the findings and the interpretation of their compositions is correct, then this would probably be the most convincing, but still not unambiguous biosignature to date. If the samples are returned to Earth and the findings are extended with other analyses, then we probably would have detected fossil life on Mars. In my opinion, that would validate the idea that Martian life existed, and further exploration is warranted. We would then want to know if that life was similar or different from terrestrial life to shed light on abiogenesis or panspermia between Earth and Mars. As the formation of the Moon would have been very destructive, if life emerged on Mars and was spread to Earth, this might provide more time for living cells to evolve compared to the conditions on Earth. It would also stimulate the search for subsurface life on Mars, where interior heat and water between rock grains would support such a niche habitat as it does on Earth.
It seems a pity that without an MSR, we may have the evidence for Martian fossil life, packaged for analysis, but kept frustratingly remote and unavailable, mere millions of kilometers distant.
The paper is Hurowitz, J.A., Tice, M.M., Allwood, A.C. et al. “Redox-driven mineral and organic associations in Jezero Crater, Mars.” Nature 645, 332–340 (2025). https://doi.org/10.1038/s41586-025-09413-0
Other readings
Tolley A, (2022) Venus Life Finder: Scooping Big Science web: https://www.centauri-dreams.org/2022/06/03/venus-life-finder-scooping-big-science/
Walker, S. I., Mathis, C., Marshall, S., & Cronin, L. (2024). “Experimentally measured assembly indices are required to determine the threshold for life.” Journal of the Royal Society Interface, 21(220). https://doi.org/10.1098/rsif.2024.0367
Twenty years ago I thought life on Mars was impossible, but now it might be possible that Mars was wet long enough to have produced life. If not, then I doubt there is any non indigenous life there. Getting a sample from ancient subsurface ice or rock where water once ran is ideal. I agree with the justification for going there to find life.
If Mars’ warm, wet period ended about 3.5 bya, I don’t know what evidence of life we could find. Stromatolite bands in rocks like those in Australia? I cannot imagine there is any organic material representing DNA/RNA/proteins. If the carbon the rover instruments detected was some remains of life, it must have been exposed for possibly billions of years. What could be left other than a carbon isotope ratio? Chiral compounds become racemic after a much shorter time, especially if exposed. If the samples are ever returned to Earth, it will be interesting to see what tests can be done to determine their origin.
If life was once on Mars, perhaps it may still be extant in the crust, protected from the cold, dry, low atmospheric pressure on the surface. Deep drilling into the crustal rocks, perhaps where water is still liquid, might be an option, perhaps when a base is established, sometime this century. Perhaps the best approach is to drill sideways into a canyon rock face if there is evidence that water is seeping out periodically, or perhaps closer to the northern pole where water is closer to the surface, and the depth is shallower where there is a warm spot. It may be a long shot, but if the base needs to drill for water anyway, one might as well do some science as well.
As Jezero crater once had water, perhaps that might be a good location to drill deep below the surface sediments to reach rocks that are above freezing. Deep drilling is a non-trivial operation, and currently well beyond the capability of robots.
The Jezero crater appeared to be a good site for this investigation and it has been conducted pretty much as planned. Perhaps what more we could expect from the Perseverance mission is that an effective means to obtain the samples thus far be worked out. But I have to wonder if Jezero is going to reveal much more about life to this Rover. It it something akin to the dilemma left by Viking biochemical tests, only with treads.
So what’s an alternative?
Mars does still have a hydrosphere, suggesting that somewhere subsurface there should be “pooling: of H2O. I hesitate to say liquid water, but water is transported about Mars somehow and more than one way. Considering how much we have heard about trying to sample fluids on Europa or Enceladus, it ought to be easier to drill into a possible liquid water table on Mars and check for biological traces. A subsurface element of the hydrosphere just might circulate more organic chemical evidence of previous less sterilized eras or perhaps even leads to where hot springs host some form of what we would consider extremophiles on Earth.
The surface, as indicated, gives some indication of previous eras where life might have been responsible for tracks, or chemical formations, agreed. But if this surface has been in much the same state as it is now for a billion years or even hundred million years, perhaps our searches for ancient life are handicapped by comparison with a subsurface environment that appears to belch methane now and then, perhaps seasonally.
Of course, there is still an underlying assumption or two here. We could investigate to determine whether there was never any life, some primitive form of life earlier, or some primitive life still remaining subsurface. And if that last possibility sounds absurd, consider how much has been said in behalf of investigating Ceres further, because it might have had a more Mars like environment eons ago.
From another angle, it is one thing to get to Mars via a fleet of LOX-CH4 powered rockets. But it is another thing to survive on surface or subsurface resources until there is an opportunity to launch back. For not only is there the matter of testing for life, but also how portable water is under a chemically volatile surface influenced by high doses of UV. Contamination of the water table in arid regions on Earth is bad enough. No reason to expect tapping into a water source that is already distilled. Do we really know what we are in for if a crew has to get by out there for a martian year?
@wdk
Yes, humans living on teh surface of Mars will not be trivial.
I don’t believe the water problem is severe. Standard heating, filtration, and cleaning should create a supply of potable water, if needed some minerals if it has to be distilled for safety.
It will not be possible to prove life never existed on Mars. In teh short term, we can either find evidence of past life, or if we are very lucky, extant life. We might need large populations living on Mars for centuries before there is sufficient work to state that life has never emerged on Mars. By that time, I would expect contamination and terraforming projects to have totally muddled the situation on the surface and in the immediate subsurface. Given Zubrin’s stated POV and that of others, similarly-minded libertarians, there will be little interest in doing life searches.
While KSM’s Mars trilogy had various factions on Mars, some wanting to preserve its state, I suspect that this may not happen with the Martian population. Less philosophical ideals and more rugged living due to teh harshness of the environment.
A modification of Zubrin’s Mars Direct plan makes sense with methalox propulsion. Perseverance is already testing kit to turn CO2 and water to methane and oxygen as fuel and oxidizer. An unmanned Starship could do that in advance, guaranteeing an early return flight if needed. Extra O2 can be extracted from the perchlorates that contaminate the Martian regolith.
Now, what the population is going to do to generate the income for trade to ensure Earth keeps supplies coming is another story.
Life might not exist today since Mars is very inhospitable. The time is a problem as Alex Tolley has mentioned. Mars did not have a giant impact like Earth so that gives a little more time to evolve than on Earth. There might be fossils also in lakes, and ancient ocean beds in the permafrost where they might not have been damaged by solar radiation, etc. Fossils are still possible and we might have to go there and take some rock samples back from many places.
@geofrey
Even a hint that a separate abiogenesis occurred will be very important for astrobiologists searching for life on exoplanets. Buried fossil bacterial artifacts, or minerals that could only be the product of life, would be welcome.
AI Overview
+17
In deep-sea marine sediments, microbes have been found to persist for millions of years with an exceptionally slow metabolic rate, suggesting potential doubling times on the order of thousands to tens of thousands of years. Scientists have even coined the term “aeonophiles” to describe organisms that are obligated to grow slowly over extended periods.
This extreme slow growth, almost like a state of suspended animation, is a survival strategy in environments with very limited resources. Unlike bacteria in a lab culture that can double in minutes, these microbes exist in conditions of profound energy limitation.
Deep-sea microbes
Research on microbes in deep subseafloor sediments has revealed astonishingly long lifecycles.
100-million-year survival: A 2020 study reported the resuscitation of aerobic microorganisms from sediments collected from the South Pacific Gyre, a nutrient-poor region of the ocean. The sediments, dated to between 4.3 and 101.5 million years old, contained microbes that had been metabolically active, albeit at an extremely low rate.
Multi-year doubling times: In certain deep marine sediments, the mean generation time for microbial communities has been estimated to be tens to thousands of years. Some uncultured clades like Bathyarchaeota and Thermoprofundales have estimated doubling times of several years.
Subsurface bacteria and archaea
Life in the deep terrestrial and oceanic subsurface is characterized by similar slow metabolic rates due to a lack of nutrients, space, and energy.
Long-lived permafrost microbes: Microbes isolated from Siberian permafrost have remained viable for over 100,000 years.
Deep subsurface fluids: In places like the Timmins mine in Canada, fluids can be trapped for over a billion years, allowing for the possibility of life persisting on this timescale.
Ancient salt deposits: In one controversial study, bacteria were reportedly isolated and revived from a 250-million-year-old salt inclusion. While there is ongoing debate about contamination, the findings suggest the potential for extreme longevity in some bacteria.
Why these microbes live so slowly
In these nutrient-poor, energy-limited habitats, microbes have adapted to minimize their energy consumption.
Maintenance metabolism: A large portion of their minimal energy is likely used for cell repair and maintenance rather than for growth and reproduction.
Slow growth, not dormancy: Studies have shown that many of these organisms are not simply dormant, but are metabolically active and dividing, though at an exceptionally slow pace.
Survival traits: This slow-growth strategy allows them to endure long periods of starvation and environmental stress, making them some of the most enduring life forms on Earth.
We are unlocking how frozen microbes stay alive for 100,000 years
It is amazing – and even a bit frightening – how long certain organisms can last. Of course, this bodes well for any native microorganisms on Mars who might be surviving and even thriving deep (?) under the surface of the Red Planet. After all, Mars also has huge regions of subsurface ice water.
This also makes me wonder: If these “simple” creatures can live for ages without consciously trying, what could an advanced intelligent species do in terms of longevity?
Speaking of long lives…
A recent record for this incredible ability to exist in a living state is 100 million years by some aerobic bacteria found under deep sea sediments in the Pacific Ocean:
https://www.scientificamerican.com/article/100-million-year-old-seafloor-sediment-bacteria-have-been-resuscitated/
Even more recently, scientists have found two-billion-year-old microorganisms buried in some igneous rocks from South Africa that may still be alive!
https://link.springer.com/article/10.1007/s00248-024-02434-8
And I love this animated speculation on Martian life courtesy of Walt Disney from 1957…
https://www.youtube.com/watch?v=m8pjloU1XL4&t=1s
I find it curious that some of these organisms would therefore be longer lived than the sea floor where they reside. Are they migratory? No, that’s not a serious question, just demonstrating the unreasonableness of superficial evidence of long lived organisms.
The Pacific Ocean is older than the 100 million years of the microbes found in teh sediment. Whether or not the calculations are correct, the finding cannot be discounted by the age of the ocean.
Billion-year-old microbes is another matter, unless they are still reproducing at a slow rate that stays within bounds.
I we cryo-preserved microbes as cells and not spores, and protected them from external damage, how long could they last? If nothing else, it implies that microbes embedded in frozen rocks or comets could survive long journeys across interstellar space, making a mockery of our concerns of warm, complex animal survival of even a century questionable.
I first heard about long-lived microbes in the deep ocean sediments about a decade or so ago. Since then, the discoveries of very slow metabolizing microbes have increased. Preservation of microbes has also been demonstrated by revived microbes millions of years old, which is fascinating as this means that functioning biology can be maintained rather than the organisms leaving fossil traces. Very X-Files.
I have wondered whether these microbes could provide a useful genomic sequence clock to calibrate against their more contemporary and active examples of the species.
More relevant to this post is whether it is possible that microbes in the subsurface glaciers have survived and might be extracted when drilling into the subsurface glaciers for water sources on Mars.
Thank you for this post!👍🏼
Finding the fox by its footprints or a missing chicken and a few feathers near the coop.
After his first adventure recovering tiny metallic globules from the sea floor where an interstellar meteor went down, Avi Loeb was contemplating a second expedition to look for bigger chunks, but that adventure didn’t materialize. I was hoping that they might find a well-preserved alien thumb drive or solid state drive or some such techno-artifact. Maybe one may yet be found on a forthcoming interstellar asteroid or comet.
Robin Datta – I don’t know what happened to Avi Loeb. When he started his now very off-road adventure, he said he was mainly doing this so that mainstream science would include extraterrestrial explanations into the current science paradigms. Instead, he reminds me more of Eric von Daniken and the infamous ancient astronauts ideas from the 1970s.
Sadly, Loeb is also reminding me of Harvard professor John Mack who studied those who claim to have been abducted by aliens and got lost along the way…
https://www.psychologytoday.com/us/articles/199403/the-harvard-professor-the-ufos?msockid=295f0603348667a51b4e15a235c56636
There is a very good reason why science is so rigorous. Pseudoscience doesn’t need any more help – it already has way too many supporters as it is. This isn’t just an inconvenience or even amusing: It is a genuine threat to our society.
Maybe the Chinese can bring back the samples for us…
https://www.livescience.com/space/mars/if-there-is-a-space-race-chinas-already-winning-it-nasa-unlikely-to-bring-mars-samples-back-to-earth-before-china-does-experts-say
There first attempt to land a rover on Mars was a success:
https://www.space.com/tianwen-1.html
And they have also returned samples of lunar regolith from both our natural satellite’s near and far sides:
https://en.wikipedia.org/wiki/Chinese_Lunar_Exploration_Program
Well done article, Alex. You clearly laid out the details of this important discovery for the field of extraterrestrial life and the need to get those samples back to Earth – either that or we send an advanced biolab there.
What are your thoughts on percholates and how they might affect life on Mars, especially the kind that is might actually be living there now?
https://ntrs.nasa.gov/api/citations/20190028297/downloads/20190028297.pdf
https://www.sciencedirect.com/science/article/pii/S0019103524003063
https://www.seattletimes.com/opinion/crucial-evidence-about-life-on-mars-is-stuck-on-mars/
@LJK
The chlorate and perchlorates are fairly toxic to terrestrial plants. I am old enough to recall that sodium chlorate was sold as a weedkiller. On Mars, as they are produced by surface conditions, it is probable that they do not extend deeply into the regolith, the depth depending on the turnover of the regolith.
Having said that, terrestrial prokaryotes can use chlorates and perchlorates for energy and are therefore suitable for detoxifying the Martian regolith for agriculture.
There is a CD post about remediating the Martian regolith: Mars Agriculture – Knowledge Gaps for Regolith Preparation.
As for indigenous Martian life, there are two possibilities. Firstly, they live in niches well away from the surface in crustal rocks where the conditions allow for liquid water. Secondly, like terrestrial organisms that can use these molecules, there could be life just beneath the surface, protected from radiation, but utilizing the chlorates as an energy source.
It would be ironic if the Viking mission actually detected these microbes, but the findings were dismissed. We have been very careful to avoid doing biology on Mars for 50 years. Maybe now is the time to start thinking about it again.
This article goes into great detail on the Viking biology experiments and how they came about…
https://www.drewexmachina.com/2022/07/28/nasas-viking-mission-the-search-for-life-on-mars-the-experiments/
You may also find this video of interest…
https://www.youtube.com/watch?v=9s9UXXAmlTg
It is unfortunate how gun-shy NASA became after the ambiguous Viking results. They just had an incomplete view of the makeup of the Martian surface at the time, which in one way should have been expected considering no one had successfully landed on the Red Planet before.
I was also surprised that Viking didn’t have better methods of conducting a geological and mineralogical analysis of the Martian surface: One might think that would have been a top-tier priority in the search for life there.
Then again, when InSight landed on Mars in 2018, the mission team somehow didn’t take into account that there might be obstructing rocks under the Martian surface when they attempted to burrow seismology sensors into it, go figure.
We are talking about 1960s and early 1970s technology for teh Viking landers. I can tell you that labs in those days were very primitive by comparison to today, with very little knowledge of molecular biology. Just for reference, the structure of DNA was elucidated just 22 years earlier, genetics was studied with no understanding of what genes were, and my university had no courses on molecular biology, just biochemistry. A few proteins had been painstakingly sequenced. Electronics were still very simple. Programmable ICs with CPUs and memory were being introduced when Viking was on Mars. I can only guess at what was available when Viking was being designed. Just compare the Viking science instruments to those on Perseverance with roughly the same spacecraft mass. Today, we can pack optical spectrometers, gas chromatography, mass spectrometers, and even tiny microscopes on a probe, and control them with sophisticated software that can analyze the data locally if desired. Look at old 1960 movies of scientists staring down basic microscopes. Today, those scopes can do far more, and if portability is desired, there are tiny microscopes offering 40-100x magnification. If we had a tiny microscope with 1000x magnification, we could resolve bacteria, and that could be packed onto an icy moon probe/lander.
Since we don’t yet know if life exists or what its molecular biology is, we cannot yet sequence its DNA/RNA/proteins. But if life exists, we will be able to do that once we have the knowledge. Imagine doing environmental “alien DNA” analysis from a sub-ice-crust ocean submersible, or even a plume sampler at the surface. The first Nature/Science article about the results will be sensational. Then it will be ho-hum.
UMass Researchers Help ID New Mineral on Mars, Providing Insight on the Red Planet’s Potential to Have Supported Life
Identifying the mineral on Mars’ surface has eluded scientists for decades
Researchers from the University of Massachusetts Amherst are part of a team that has identified a unique mineral on Mars, described in Nature Communications.
Named ferric hydroxysulfate, the mineral provides clues about the Martian environment and history of the planet, including the possibility of former lava, ash or hydrothermal activity.
The full article here…
https://www.umass.edu/news/article/umass-researchers-help-id-new-mineral-mars-providing-insight-red-planets-potential
The paper online here…
https://www.nature.com/articles/s41467-025-61801-2
To quote:
“Temperature, pressure and conditions such as pH are all very important indications of what the paleoclimate was,” says Parente. He is excited about the new level of detail scientists have for understanding the Red Planet through this research. “The presence of this mineral puts a lot more nuance on what was going on. Parts of Mars have been chemically and thermally active more recently than we once believed—offering new insight into the planet’s dynamic surface and its potential to have supported life.”
It strikes me as near insane that Perseverance’s Martian samples will sit there, waiting to be picked up for lack of a few billion dollars.
Whether finings are positive, negative, panspermic, or unique; their analysis would change our understanding of biogenisis across the universe.
Humans to Mars yes, but send “Fed Ex”to get that package!
Better yet, collaborate with the European, Chinese, and Indian space agencies to bring back the goods.
As I posted in this thread above, the Chinese are seriously planning to return samples of the Martian surface to Earth. Their recent mission efforts at Luna and Mars indicate they could do it.
https://www.livescience.com/space/mars/if-there-is-a-space-race-chinas-already-winning-it-nasa-unlikely-to-bring-mars-samples-back-to-earth-before-china-does-experts-say
I wonder if that will energize the US to get the samples back? China is already overtaking the US in several technology and science endeavors. A successful Mars sample return by China could be a “Sputnik” moment for the US.
[The current mania of hyperscaling the GenAI development to reach AGI/SI may well collapse the US stock market and damage the economy, and could even allow China to become dominant. I hope sanity will prevail, but the current US zeitgeist seems to be following the 1930s German experience with regard to science (and art), and look where that led.]
I will be surprised if there is not life on Mars. If it did not evolve independently, it would have probably arrived from Earth via panspermia, probably around 4 bya.
At this time, the surface of Mars and shallow bodies of water would have been too oxidizing for it to survive, but deeper bodies of water like the Great Northern Ocean would most likely have been anaerobic in their lower reaches. As Mars dried out and froze, this life would have retreated, following the liquid layer into the crust becoming like the slow metabolizing aeonophiles deep in Earth’s crust today.
The question will be is the life we find native, or did it come from Earth, or did Earth’s life come from Mars?