I think life evolved here, and if it evolved elsewhere it was independent. But that's a belief. Assuming that all DNA can be categorized as contamination or not is perhaps a bit of folly. If all that can be found are fragments, it's not for sure they are or aren't brought from modern times earth.I consider the "earth life was seeded from elsewhere" theory REALLY remote. But am not willing to rule it out entirely absent evidence.And yet I still think that Curiousity should go investigate this wet area.
Sooner or later humans—biped rovers that can’t be sterilized—will set foot on the planet, hopelessly confounding any hope of finding indigenous life, I find this statement staggeringly silly. If true then it would be impossible to determine the ancestry of life on earth because of cross contamination.
That largely rules out putting scientific instruments on that collection rover. “I’m sure somebody’s going to ask me to add science,” he said, “and they better have a really, really, really good argument.”
Quote from: Blackstar on 08/28/2017 09:59 pmThat largely rules out putting scientific instruments on that collection rover. “I’m sure somebody’s going to ask me to add science,” he said, “and they better have a really, really, really good argument.”In other words, this idea won't go anywhere.
I think it's more likely that if life started on Mars it could have either seeded Earth or vice a versa. The two planets exchange so much material that this likelihood must be considered reasonable high that if life occurred Mars that both planets have a common origin.
Quote from: Star One on 08/09/2017 08:08 amI think it's more likely that if life started on Mars it could have either seeded Earth or vice a versa. The two planets exchange so much material that this likelihood must be considered reasonable high that if life occurred Mars that both planets have a common origin.And I think it's entirely conceivable that the whole idea of planetary protection is unworkable because every solid body of any meaningful size in the solar system up to the kuiper belt may already be contaminated by earthly (or wherever they arose) bacteria. Just due to their sheer numbers, resilience and the four billion years they have existed.
Decades of robotic exploration have confirmed that in the distant past, Mars was warmer and wetter and its surface was habitable. However, none of the spacecraft missions to Mars have included among their scientific objectives the exploration of Special Regions, those places on the planet that could be inhabited by extant martian life or where terrestrial microorganisms might replicate. A major reason for this is because of Planetary Protection constraints, which are implemented to protect Mars from terrestrial biological contamination. At the same time, plans are being drafted to send humans to Mars during the 2030 decade, both from international space agencies and the private sector. We argue here that these two parallel strategies for the exploration of Mars (i.e., delaying any efforts for the biological reconnaissance of Mars during the next two or three decades and then directly sending human missions to the planet) demand reconsideration because once an astronaut sets foot on Mars, Planetary Protection policies as we conceive them today will no longer be valid as human arrival will inevitably increase the introduction of terrestrial and organic contaminants and that could jeopardize the identification of indigenous martian life. In this study, we advocate for reassessment over the relationships between robotic searches, paying increased attention to proactive astrobiological investigation and sampling of areas more likely to host indigenous life, and fundamentally doing this in advance of manned missions. Key Words: Contamination—Earth Mars—Planetary Protection—Search for life (biosignatures). Astrobiology 17, 962–970.
This paper seems appropriate for this thread.Searching for Life on Mars Before It Is Too LateQuote Decades of robotic exploration have confirmed that in the distant past, Mars was warmer and wetter and its surface was habitable. However, none of the spacecraft missions to Mars have included among their scientific objectives the exploration of Special Regions, those places on the planet that could be inhabited by extant martian life or where terrestrial microorganisms might replicate. A major reason for this is because of Planetary Protection constraints, which are implemented to protect Mars from terrestrial biological contamination. At the same time, plans are being drafted to send humans to Mars during the 2030 decade, both from international space agencies and the private sector. We argue here that these two parallel strategies for the exploration of Mars (i.e., delaying any efforts for the biological reconnaissance of Mars during the next two or three decades and then directly sending human missions to the planet) demand reconsideration because once an astronaut sets foot on Mars, Planetary Protection policies as we conceive them today will no longer be valid as human arrival will inevitably increase the introduction of terrestrial and organic contaminants and that could jeopardize the identification of indigenous martian life. In this study, we advocate for reassessment over the relationships between robotic searches, paying increased attention to proactive astrobiological investigation and sampling of areas more likely to host indigenous life, and fundamentally doing this in advance of manned missions. Key Words: Contamination—Earth Mars—Planetary Protection—Search for life (biosignatures). Astrobiology 17, 962–970.Rest of the paper.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5655416/
This task is not simple, and yes there is a conflict between protecting these hypothetical life forms from human exploration activities. We not only need to consider "contamination", but also destruction of these potential life forms by consumption or changing environmetal parameters. Bacteria from earth may simply eat them up, phages could find them a good place to replicate, unicellular or multicellular eukaryotic organisms could also start to wipe them out.
(2) Conservation areas may not only protect the martian life forms from anthropogenic interfereces, but also protect astronauts from any negative impact caused by these organisms on human physiology. The trick could be to find almost completely sterile regions on Mars and send the first settlers there and isolated them as good as possible from the environment. They have to live in enclosed structures anyway to ensure permanent life support. It should not be a big problem to sterilize anything what humans throw away or deposit on Mars. The necessary infrastructur should be part of the first logistics missions. Recycling is mandatory where ever possible.
Even if it turns out, what most scientists assume, that Mars does not harbor any active life forms, planetary protection issues must not be underestimated and need to be weighted carefully against our desire to discover and explore.
likewise it is extremely unlikely that organisms adapted to martian conditions, will survive in the human body. It is just too hostile for them.
Unfortunately what is happening is that planetary protection is more likely to be over-estimated rather than under-estimated.
Quote from: Dalhousie on 05/13/2018 06:12 amlikewise it is extremely unlikely that organisms adapted to martian conditions, will survive in the human body. It is just too hostile for them.Pretty much everyone who works on the subject agrees it's "unlikely". The problem is we have no basis to quantify how unlikely. So if your requirement is, say, to ensure the probability of back contamination to earth is less then 1 in a million, you can just say that "the odds of Mars life being able to infect Earth live are lower than that so we're done."QuoteUnfortunately what is happening is that planetary protection is more likely to be over-estimated rather than under-estimated.There's important context for the increasing paranoia of PP: We kept thinking that life wouldn't survive in various environments, and then finding it in those environments when instrumentation improved. Undoubtedly this must end somewhere, but the experience suggests that a gut instinct "nothing can survive that" isn't reliable.