4 ms·

Weak evidence for life, at best. Which is why exploration continues, to search for stronger evidence. If irrefutable evidence of life were found it would open u

by nkrisc 4mo ago

Weak evidence for life, at best. Which is why exploration continues, to search for stronger evidence. If irrefutable evidence of life were found it would open up many new avenues of exploration and research that would need funding, with strong justification - much stronger justification than currently exists.

nephihaha 4mo ago
I don't think it was weak at all. We got two positive results from the Viking landers and then tried to explain them away. There is a lot of circumstantial evidence, which combined builds up a case. The public believe we should be looking for cities and skeletons, when in fact we should be looking for extremophiles. It is possible that some of these are due to cross-contamination within the solar system (before human intervention), but that is another matter.
- nkrisc 4mo ago
  Two positive results that had non-biological explanations and a lack of any other significant evidence. Extreme skepticism is warranted.
  - nephihaha 4mo ago
    They are best thought of as circumstantial evidence, especially when combined with the various other possible indicators we have detected on Mars. Many books I have read over the years talk about the Viking experiments as if they had disproved life, whereas they did no such thing. However, I think the bulk of life on Mars – if it exists – is probably underground. Conditions there are much less hostile than the immediate surface. Since Viking, we continue to find Earth life in extreme environments including high altitudes and deep underground. Microbes can be much tougher than animals.
- somedude89897 4mo ago
  The two Viking landers, 6500km apart, had positive results. That would suggest that life is widespread and close to the surface. But the atmosphere of Mars is in chemical equilibrium, which means life can't be widespread and close to the surface because it is not affecting the atmosphere. If life is present on Mars it would have to be deep underground, perhaps in a geothermally heated brine lake, which would be very hard to detect with current technology. The Viking data was probably non-biological, it really isn't strong evidence for life today.
  - nephihaha 4mo ago
    There are questions about methane in the Martian atmosphere. Again, there is some ambiguity as to why. However, we have found life in some very hostile environments on Earth, notably high up in the atmosphere. Planococcus halocryophilus can exist on Earth at -20' C, well within Martian surface temperature ranges, and is tolerant of very salty water. Microbes need a fraction of the resources we do, and some can exist in very small numbers for long periods before better conditions come along. Surface temperatures on Mars have been observed to go over 20' C during the day in some places which may allow for some warmth to penetrate rock and dust. A very hostile environment, to be sure. https://www.nature.com/articles/ismej20138 https://www.nature.com/articles/ismej20138

by nkrisc 4mo ago

nephihaha 4mo ago

I don't think it was weak at all. We got two positive results from the Viking landers and then tried to explain them away. There is a lot of circumstantial evidence, which combined builds up a case. The public believe we should be looking for cities and skeletons, when in fact we should be looking for extremophiles. It is possible that some of these are due to cross-contamination within the solar system (before human intervention), but that is another matter.

nkrisc 4mo ago
Two positive results that had non-biological explanations and a lack of any other significant evidence. Extreme skepticism is warranted.
- nephihaha 4mo ago
  They are best thought of as circumstantial evidence, especially when combined with the various other possible indicators we have detected on Mars. Many books I have read over the years talk about the Viking experiments as if they had disproved life, whereas they did no such thing. However, I think the bulk of life on Mars – if it exists – is probably underground. Conditions there are much less hostile than the immediate surface. Since Viking, we continue to find Earth life in extreme environments including high altitudes and deep underground. Microbes can be much tougher than animals.
somedude89897 4mo ago
The two Viking landers, 6500km apart, had positive results. That would suggest that life is widespread and close to the surface. But the atmosphere of Mars is in chemical equilibrium, which means life can't be widespread and close to the surface because it is not affecting the atmosphere. If life is present on Mars it would have to be deep underground, perhaps in a geothermally heated brine lake, which would be very hard to detect with current technology. The Viking data was probably non-biological, it really isn't strong evidence for life today.
- nephihaha 4mo ago
  There are questions about methane in the Martian atmosphere. Again, there is some ambiguity as to why. However, we have found life in some very hostile environments on Earth, notably high up in the atmosphere. Planococcus halocryophilus can exist on Earth at -20' C, well within Martian surface temperature ranges, and is tolerant of very salty water. Microbes need a fraction of the resources we do, and some can exist in very small numbers for long periods before better conditions come along. Surface temperatures on Mars have been observed to go over 20' C during the day in some places which may allow for some warmth to penetrate rock and dust. A very hostile environment, to be sure. https://www.nature.com/articles/ismej20138 https://www.nature.com/articles/ismej20138