The absence of persistant liquid water and the punishingly hard UV make the surface a poor biome for life that shares our penchant for moisture and amino acids.

One wouldn't look in the least likely location, would one?

It is based on assumption that there was surface life in past. The condition was much more favorable than now. But presently the surface is very dry desert and without suitable atmosphere. If life ever existed on the surface, the only way to survive was moving under the surface.

Thank you Dr Jan Balaz for your clarification. Well Appreciated.

Yes, life can exit underground for millions of years. Even on earth micro-organisms are found in hot springs and even several hundred meters under water and has survived freezing temperature. On Mars there are several geographical locations (like the ice capped mountain in the south pole https://mars.nasa.gov/news/1001/nasa-orbiter-penetrates-mysteries-of-martian-ice-cap/ ) and active geology (active lava tubes ) can foster life for a long period of time.

However we cant expect the same type of life as on Earth to be found on Mars. If we do find life on mars it will be in form of single cell micro-organism confined to few colonies. Also their cell internal structure may not consist of DNA, Nucleus, mitochondria etc.; but some other alternative forms. This is what makes journey to Mars more interesting. We don't know what kinds of life form we may find on Mars. On Earth we have found life taking refuge (even mutated) under severe environment conditions, and we hope that the same would have happened on Mars.

In the past all NASA missions has been exploring the surface of Mars, and non of them could find life. the only option remains is to dig deeper (at-least 100 to 200 feet) into the Mars surface (covered in ice or key zones). And to do so we need some serious space hardware.

Thanks,

just recently I believe at SURF (Stanford Research Research Facility) Lead SD, home of the LX and DUNE experiment, a mile underground, in the middle of the rock they were excavating, they found water with some type of bacteria in it. Will try to find the link, no light, no O2.

Well, today it is my birthday and I decided I would make myself a nice present. It's been more than fifty years that I have been waiting for knowing whether extra-terrestrial life was something common or not, not talking here of intelligent life but of micro-organisms or something comparable. I thought that after having been waiting for 44 years for a new LR-experiment to be embarked on a martian probe, and disappointed that it never was, I had to acknowledge the reality. NASA knew and know. So do I today. I'm putting short a long story, a story of 44 years.

Sometimes it takes a long time to getting closer to the truth. In 1976 Viking landed on Chryse and Utopia planitiae. The LR experiment was performed as per the design of Gilbert Levin to search for life. https://www.gillevin.com/

The LR experiences delivered positive results at both sites, the radioactively «tagged » food had been metabolized by micro-organisms. But stating that life had been discovered, such a miserable form of life, and that was it, would have certainly brought to an end the exploration of Mars and NASA's credits in that respect. This is acknowledged 40 years later by David Williams (2016) who is the planetary curation scientist for the NASA Space Science Data Coordinated Archive at Goddard Space Flight Center in Greenbelt, Maryland "The data were very controversial," Williams said. "But, in a way, it helped push for continued Mars missions and landers. The very next missions were planned around what we found with Viking, and then the next group of missions built upon those. But even our most current Mars missions still refer back to Viking."

Therefore, it was better to conclude otherwise (than a positive) and NASA did. The rationale to do so at the time was based on two major arguments: that there was no free water on Mars and that the other experiments had concluded that there was no organic matter, nope. What they did not say is that by heating the sample, the chemical properties of the Martian soil (perchlorates) had probably lead to the dissociation of the organic content before the analysis (Navarro-González et al., 2010). Furthermore, further re-analysis by Giorgio Bianciardi et al. of the data showed “The presence of circadian rhythmicity and a high degree of mathematical complexity or order in the LR data most likely means Viking discovered microbial life on Mars over 35 years ago" Article Complexity Analysis of the Viking Labeled Release Experiments

The story in short is here: https://bgr.com/2019/10/16/mars-life-nasa-gilbert-levin-viking/ and one can sense that searching for life is the essential money-making machine used by NASA to keep things going, even looking for where there is no chance to find it as « to looking for biosignatures in the atmospheres of planets outside our solar system ». They say it black on white.

But since then, water has been found on Mars and organic matter as well as Curiosity made clear that there are thiophenes, methylthiophenes methanethiol and dimethylsulfide, etc. Dirk Schulze Makuch, study author and Washington State University astrobiologist says "If you find thiophenes on Earth, then you would think they are biological, but on Mars, of course... » things are different.... in the end « It's possible that impacts by meteors delivered thiophenes » good joke:-)

Nice play but no cigar...

One thing for sure, NASA is so much trying to find life on Mars that they never included in any other mission any other device to do so and certainly not included Gilbert Levin experiences again. They claimed that the LR was contaminated in 1976 with organic compounds coming from Earth; it would have been so easy to try again after ensuring that it was not the case. Too easy for sure.

As Schulze Makuch adds, it may take landing humans on Mars, in addition to robotic explorers, to learn the truth."I think the proof will really require that we actually send people there, and an astronaut looks through a microscope and sees a moving microbe." No doubt, they want to keep things going.

I known nothing (especially in that case), but I have learnt to know that I should not believe what I am told and I strive to do so.

This will be a fantastic subject for future historians of science (epistemology).

At least, I have decided that it will be a nice present for my 60th anniversary. I have decided that given all the above I have the answer to the question I have been asking myself for more than 50 years. If micro-organisms exist on Mars, and they do, then life is common in the Universe.

The unfortunate thing comes from SETI and other efforts, intelligent life might as rare as micro-organisms could be ubiquitous.

Regards to all.

Patrice Poyet

• Navarro-González, R., et al., 2010. Reanalysis of the Viking results suggests perchlorate and organics at midlatitudes on Mars. Journal of Geophysical Research, Vol. 115, Issue E12, https://doi.org/10.1029/2010JE003599
• Williams, D., 2016. https://www.nasa.gov/feature/goddard/2016/nasas-viking-data-lives-on-inspires-40-years-later Share

thats easy, because they are spending money looking for it. The next landing from NASA will be to drill core samples and store them on board the lander, waiting to be picked up to come back to earth for analysis. ESA has some other plans, but when you see LOTS of $ being spent, they have convinced the "board" there is a good reason to go :)

I am sure everyone must be very excited about the successful landing of Perseverance. The landing was astonishing.

NASA need reasons for mission to Mars. Generally speaking, I believe NASA can get most answers about Mars from automated missions without human presence.