"On Earth, we are used to the idea that absence of proof is not proof of absence," explains Mike Trouser, a philosopher at Madeup State University, lead author of the new research. "Similarly, just because a thing might have happened, it doesn't mean that it did happen.
"On Mars, however, we now know that these principles don't apply, and that anything not known to be stonkingly, mind-crushingly impossible must have happened."
As an example, Trouser cites a story in the Guardian on Saturday:
Microbe experiment suggests we could all be Martians
Experiments by an international team of researchers back a controversial theory that life flourished on Earth after primitive organisms arrived aboard a meteorite, itself gouged from Mars by a giant impact.
The story refers to a recent paper in Icarus, which found that various microbes and a lichen can survive being sandwiched in rock and then twanked with a steel plate, to recreate the pressures placed on known martian meteorites.
"You might think that this just shows that contemporary microbes can be twanked with a steel plate and come up smiling," says Trouser. "After all, one cannot tell from reading the abstract whether the experiments exposed the microbes to vacuum conditions, extreme temperatures or high doses of radiation." But in fact, the Guardian quotes the paper (although none of the authors, and no independent sources) as saying:
These results strongly confirm the possibility of a 'direct transfer' scenario of 'lithopanspermia' for the route from Mars to Earth, or from any Mars-like planet to other habitable planets in the same stellar system.
"A strongly confirmed possibility (whatever that is)? Please, you're being too modest," says Trouser.
Initially, Trouser was intrigued why one doesn't see similar results in any other field being reported in this manner. "One doesn't for example, regularly see articles informing us that we don't know for sure that drinking margaritas doesn't make you live longer, or that we can't be sure that cats aren't plotting to overthrow humanity," he points out. "I think the differences in Martian logic now explain this apparent anomaly."
The unique workings of Martian logic don't stop there. At the recent meeting of the American Astronomical Society, it was widely reported that the Viking landers would not have recognized — indeed, would have killed — any life form using hydrogen peroxide as a biological solvent.
The ambiguity of the Viking experiments is nothing new - they have become the grassy knoll of astrobiology. They were designed to look for biological processes — nutrient uptake, gas release — in Martian soil. All gave positive results! Trouble is, so did all nearly all (but not all) the controls. We should probably learn from the Viking experiments to try and design the next life-detectors, rather than endlessly picking over the results.
But, although he believes the existence of H2O2-based life proven, Trouser believes we should also be casting the net wider. "Never mind weird alien biochemistry," he says. "There's plenty of regular life on Mars."
As an example, he cites a 2004 article discussing the general difficulty of recognizing as alive anything that doesn't give you an anal probe and say 'Take me to your leader'. In it, referring to how better we are at spotting microbes now than then, Andrew Steele of the NASA Astrobiology Institute at the Carnegie Institution of Washington says: 'There could have been 10 million bacteria per gram of martian soil, and Viking wouldn't have seen them.'"
"What we now know Steele should have said," says Trouser, "is that there are 10 million bacteria in every gram of Martian soil. For all we know, the Viking mission missed spotting the Flying Spaghetti Monster," he adds. "Hail, then, Martian Flying Spaghetti Monster!"