I don’t know why this story hasn’t gotten more attention in the mainstream media. This National Geographic article summarizes the experiments done by Voyager 1 and 2 in 1976 that showed strong evidence of microbial life in the Martian soil.
For some reason, NASA hasn’t done experiments with any of the later probes to confirm and then image what the microbes actually are or what they look like. :dubious: I would have thought this would have been one of the biggest stories of the 20th century but it went nowhere. Maybe the government and science believed in 1976 that people just couldn’t handle the news of even the tinniest Martian life.
It is only a recent reanalysis of the data by top scientists that confirms they almost certainly found life back then that drew any attention to it again. There is another probe headed to Mars soon but it doesn’t have a microscope to image whatever it is either. The best it can do is another indirect confirmation. Mind-boggling.
Were you aware of this at all? I only heard about it a couple of weeks ago and I have always followed science news fairly closely.
At the time, the production of gas was attributed to some effervescent quality of the soil, unrelated to microbial processes. Some said the absence of an ozone layer allows high levels of UV radiation to produce peroxides and perchlorates in the the soil, which reacted with the culture medium. Still not conclusive though.
This was mentioned in the book “13 Things That Don’t Make Sense”. I think the thing is, the evidence can be interpreted in several ways, so it’s not convincing that there’s life on Mars.
The Viking experiments have certainly been discussed extensively, the recent complexity theoretic analysis just being the latest addition to that discussion. Like the fossil ‘microbes’ in ALH840001 and other Mars meteorites, though, whenever someone argues the pro-life side, a study arguing the opposite is usually not far behind. Part of the problem is that the labeled-release experiment, which is where the Viking evidence comes from, was just one of three designed to detect extraterrestrial life on the Viking landers, and the other two found nothing, so today as then, the evidence is just too inconclusive to firmly announce something as paradigm-changing as the discovery of extraterrestrial life.
Note, however, that this is not the only evidence for Martian life: apart from the aforementioned meteorite ‘fossils’, there’s also the presence of methane, which is unstable and so necessitates an active source; this could be either geological or biological, but according to current knowledge, Mars is not geologically active (enough) to produce the observed levels of methane. People have grown methanogenic bacteria under simulated Martian conditions, and they indeed were able to survive, and even prosper. (Here’s a link to the study (pdf).) Also, some kinds of lichen have been found to withstand Martian conditions (see here). Furthermore, there are the ‘dark spots’ around Martian geysers, which have been hypothesized to be due to photosynthetic organisms.
There were experiments conducted at Cornell University, in the 1960’s, where earth organisms were kept in Martian conditions (“Mars Jars”). Even back then, it was found that many organisms could live under Mars conditions.
I am more interested in the possibility of finding evidence of past life (coral, shells, fossils). Does the new probe have the ability to detect this stuff?
Although Curiosity is not equipped with an optical microscope as such, it has a camera that’s capable of resolving down to a level of 14 micrometres per pixel - in practical terms, that means if it found a tiny chessboard only 1mm square, it would be able to image it, and each square on the chessboard would be about 10 by 10 pixels in the image.
That’s not quite good enough to be able to resolve details of anything on the scale of single-celled organisms we have on Earth, but if there are intact remains on Mars of anything similar to multicellular organisms here, (or, of course, if there are any tiny Martian chessboards) this camera would be able to photograph it.