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Here's one from 2010: https://spaceflightnow.com/news/n1001/09marslife/ https://spaceflightnow.com/news/n1001/09marslife/ I think there's a more recent book t

Here's one from 2010: https://spaceflightnow.com/news/n1001/09marslife/ https://spaceflightnow.com/news/n1001/09marslife/ I think there's a more recent book that came out a few years ago, but a quick google search isn't finding the name, sorry. For Wikipedia which relies on citations, it's going to reflect the majority opinion which is "ALH84001 is insufficient evidence for life." However the reasoning for saying that morphological features are insufficient signs of life (in contrast with biologists studying Earth life who routinely rely on such evidence) is actually a direct response to ALH84001. Like the Pluto-Is-A-Planet? debacle, the generally accepted requirements and definitions were drawn up after the fact specifically to exclude ALH84001, in order to end an embarrassing controversy and provide funding for more missions (why go to Mars when you can just pick up rocks in Antarctica instead?) rather than answer a scientific question.

dekhn 6y ago
we're still in the same place as the original publications: most scientists don't think that EM of rocks from that look like microbes on rocks on earth is a convincing argument. The morphological argument has held since before this rock, it wasn't added up afterwards. There just isn't enough information here to conclude anything so it's easier to reject the hypothesis (I have to admit, it took me a while to accept the idea that there is that much mass exchange between planets in the first place!)
- garmaine 6y ago
  And yet, go try to find out an age for the origin of life on Earth. You'll find that ALL of the evidence is faint morphological features in rocks from Australia. It's the gold standard for one field, but circumstantial in another?
  - dekhn 6y ago
    Not correct, the data on earth that is reliable is based on carbon ratios, which are a far better hallmark. The older morphological stuff, while fun, is really just speculative, still.
    - garmaine 6y ago
      Not for origin of life, no. We’re talking >3gy. These fossils are rocks, not biomaterials. Isotopes of trace decay products in the rock itself are used to age it, as is done with other geologic samples.

dekhn 6y ago

we're still in the same place as the original publications: most scientists don't think that EM of rocks from that look like microbes on rocks on earth is a convincing argument. The morphological argument has held since before this rock, it wasn't added up afterwards. There just isn't enough information here to conclude anything so it's easier to reject the hypothesis (I have to admit, it took me a while to accept the idea that there is that much mass exchange between planets in the first place!)

garmaine 6y ago
And yet, go try to find out an age for the origin of life on Earth. You'll find that ALL of the evidence is faint morphological features in rocks from Australia. It's the gold standard for one field, but circumstantial in another?
- dekhn 6y ago
  Not correct, the data on earth that is reliable is based on carbon ratios, which are a far better hallmark. The older morphological stuff, while fun, is really just speculative, still.
  - garmaine 6y ago
    Not for origin of life, no. We’re talking >3gy. These fossils are rocks, not biomaterials. Isotopes of trace decay products in the rock itself are used to age it, as is done with other geologic samples.