Quote from: JohnFornaro on 10/25/2012 08:19 pmI trust it was sterile methane. It was not seen fit to flush that system and maybe fill it with helium or some other inert gas before leaving Earth?What do mean by "sterile methane"? CH4 is CH4Also, even if you flush a system with an inert gas, trace molecules of CH4, etc. can rest because of adsorption, absorption and migration onto/into the material surfaces. In a vacuum environment, they then outgas and can be observed with a sensitive detector.
I trust it was sterile methane. It was not seen fit to flush that system and maybe fill it with helium or some other inert gas before leaving Earth?
John has a default assumption that most of the people who work in the space field are incompetent.
Thanks.I was under the impression that this would be a bit more ambiguous for Mars since we don't have a baseline of geologically produced CH4 to compare any detected biologically produced CH4 to.Is there really a specific relative 13C abundance above which we can safely say "this has to be produced by life"?Edit: I see your edit now.
If C12 is enhanced compared to C13 above these levels then this hints at a biological origin, but we do not know if potential life on Mars is as selective as life on Earth as far as C12 uptake. Anything more would seem very speculative.
Quote from: fthurber on 10/26/2012 08:00 pmIf C12 is enhanced compared to C13 above these levels then this hints at a biological origin, but we do not know if potential life on Mars is as selective as life on Earth as far as C12 uptake. Anything more would seem very speculative.Note incidentally that when talking methane it's 13C:14C that we're interested in. 12C is the more common marker, but it's used in different contexts.Putting that aside as a typo, I think you've got it backwards. If 13C is enhanced it would be a strong sign of life, as there's no known abiological process that can sort between different isotopes of carbon.Rather, if the ratio looks normal it would not rule out Martian life because Martian life may not be as selective as ours.(On the other hand, even very simple life forms on Earth are so it would be somewhat suggestive that Mars is dead.)
Are you sure about this Quindar? I seem to remember that TLS is specifically designed to measure carbon-12 to carbon-13 isotopic ratios in methane not carbon-14. As far as I know terrestrial plant life will preferentially use C12 versus C13.
Do you know btw how life sorts out isotopes? I mean in chemistry isotopes are not distinguishable. There's clearly a density difference, but this only shows up if you ave a vertical buoyancy-based separator - shouldn't make a difference within the context of a chemical reaction.
Do you know btw how life sorts out isotopes? I mean in chemistry isotopes are not distinguishable. There's clearly a density difference, but this only shows up if you ave a vertical buoyancy-based separator - shouldn't make a difference within the context of a chemical reaction.Just curious about the mechanism here.
The heavier isotope forms slightly stronger bonds
Like gravitational potential of a single neutron slightly stronger?
It's photosynthesis that does it particularly
I think Van der waals forces are forces between dipoles , permanent or induced. How is an uncharged neutron going to affect that? Does in increase the dipole moment? and how?
Also: Space is cool.