Yes, I don't understand that either. Except perhaps - that microfossils would probably be controversial - after all these look pretty life-like
So can get things that look like life - but without a way to detect biosignatures and organics, not going to be easy to test for life.
And would be no organics left in ancient life on the surface. Now if there was present day life - that might be a different thing - might be able to watch it metabolizing and e.g. a series of images showing cells dividing or whatever - but Curiosity is not sterilized to the levels needed to search for present day life even if it did find a habitat for it.
I hope they do get to send a microscope to Mars. Just to see what it is like at the microscopic level - even if it does give ambiguous results - would be good to know and scientists can then start to wonder what it means.
The highest resolution imaging device sent to Mars is the atomic force "microscope" on Phoenix, which gave very detailed images of dust grains - well beyond optical resolution - but not ideal for looking for present day or fossil microbes.
Mars Dust Grains Imaged by Atomic Force Microscope
No colour, not visible light - just a 3D Map of the external structure of the dust grains.
They do have optical microscopes of a sort - but they are more like a geologist's "hand lens" - the Phoenix optical "microscope" had a resolution of 4 microns per pixel. You'd spot the larger microbes but not smaller ones like many of the archaea.
Microscopy, Electrochemistry, and Conductivity Analyzer (MECA)
Curiosity has a resolution of 14.5 micrometers per pixel so can only spot really large microbes.
Mars Hand Lens Imager
None of them are close to the diffraction limited optical resolution of a good modern optical microscope of 0.2 microns.
But - weren't at all conclusive. This is from the
Allan Hills 84001 meteorite - the one that NASA for a while thought proved that Mars had life in the past - but then they found alternative non life explanations - and the forms in it are too small for present day Earth life (but about the right size for life that must have existed on Earth before modern life evolved).
So can get things that look like life - but without a way to detect biosignatures and organics, not going to be easy to test for life.
And would be no organics left in ancient life on the surface. Now if there was present day life - that might be a different thing - might be able to watch it metabolizing and e.g. a series of images showing cells dividing or whatever - but Curiosity is not sterilized to the levels needed to search for present day life even if it did find a habitat for it.
I hope they do get to send a microscope to Mars. Just to see what it is like at the microscopic level - even if it does give ambiguous results - would be good to know and scientists can then start to wonder what it means.
The highest resolution imaging device sent to Mars is the atomic force "microscope" on Phoenix, which gave very detailed images of dust grains - well beyond optical resolution - but not ideal for looking for present day or fossil microbes.
No colour, not visible light - just a 3D Map of the external structure of the dust grains.
They do have optical microscopes of a sort - but they are more like a geologist's "hand lens" - the Phoenix optical "microscope" had a resolution of 4 microns per pixel. You'd spot the larger microbes but not smaller ones like many of the archaea.
Microscopy, Electrochemistry, and Conductivity Analyzer (MECA)
Curiosity has a resolution of 14.5 micrometers per pixel so can only spot really large microbes.
Mars Hand Lens Imager
None of them are close to the diffraction limited optical resolution of a good modern optical microscope of 0.2 microns.
About the Author
Robert Walker
Writer of articles on Mars and Space issues - Software Developer of Tune Smithy, Bounce Metronome etc.Studied at Wolfson College, Oxford
Lives in Isle of Mull
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