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Story
Curiosity rover finds large carbonate deposits on Mars
> data from three of Curiosity's drill sites had siderite, an iron carbonate material, within sulfate-rich layers...

The article makes this sound related to atmospheric CO2, so not 'carbon' as I had initially hoped from the headline -- carbon like coal, ie, from life.

But atmospheric CO2 and a water cycle may match Earth-like conditions for life?

I did not see a date in the article, ie, how many million years ago this carbon layer was formed.

The term "carbonate" always, AFAIK, refers specifically to minerals containing the carbonate ion, CO3 with 2- charge. It's nothing particularly to do with coal or similar carbon sources. In this case, iron carbonate.
iron, CO², sulfur, water, and related compounds, sounds like there was water with a low ph, which would leach out all sorts of elements from the rocks and "soil" of mars the implication bieng that there was a varity of "soups" possibly condusive for life to occur, or take hold in. and even if not, there are now confirmed surface deposits of elements snd minerals usefull for any potential humans setting up shop on mars.....think, rocket fuel and the elements needed for growing food in greenhouses * still need to find a big pile of nitrogen compounds before getting excited* rocket
On a young planet, all water has a low pH, because it is formed by the condensation of the gaseous part of the matter ejected by volcanism, which consists mainly of water, carbon dioxide, sulfurous gases and halogen hydrides, where all substances but water are acids.

In the next few hundred millions years after a planet has cooled enough to be covered by liquid water, the water becomes gradually neutralized by leaching mainly potassium, magnesium, sodium and calcium ions from the igneous rocks (smaller amounts of iron(II), manganese(II) and other ions are also leached).

The chemical elements that are required for the appearance of life are ubiquitous.

What is much rarer is to have a planet of the right size, orbiting around a stable star at the right distance and having an adequate source of internal heat that can provide indirectly the source of chemical energy for the first living beings, and also the occurrence at the right place of certain minerals such as Fe-Co-Ni sulfides, that can catalyze the formation of complex organic molecules, before their role is taken by organic enzymes.

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  • sfn42
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  • 3 weeks ago
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O2 is the oxygen gas molecule. Two oxygen atoms stuck together. CO2 is carbon dioxide, a molecule with one carbon atom and two oxygen atoms.
I believe that you are using ASCII to approximate the chemical formula, which really does depend on subscripts to be accurate. I'm simply being facetious in the GP, but superscript is really beyond inaccurate, IMHO. Superscript means other things entirely. Don't you agree that's more confusing than collapsing it into ASCII?

https://en.wikipedia.org/wiki/Chemical_formula

https://en.wikipedia.org/wiki/Simplified_Molecular_Input_Lin...

The Simplified Molecular Input Line Entry System (SMILES) is a specification in the form of a line notation for describing the structure of chemical species using short ASCII strings. SMILES strings can be imported by most molecule editors for conversion back into two-dimensional drawings or three-dimensional models of the molecules.

Double, triple, and quadruple bonds are represented by the symbols =, #, and $ respectively as illustrated by the SMILES O=C=O (carbon dioxide...)

Only the presence of CO2 and water does not say anything about conditions favorable for life.

These are some of the most abundant substances in the entire Universe. On any medium-size planet without life, the atmosphere is expected to be composed mostly of CO2, together with a smaller amount of dinitrogen, like it is today on Venus. Also the rarefied atmosphere of Mars contains mostly CO2.

Because most rocks containing carbonates and sulfates are formed by precipitation from water, this discovery is just additional evidence that in the past Mars had much more water than today, so that there was some water lake or sea where these rocks are located now.

The atmosphere of the early Earth must have been composed mostly of CO2 too, before algae have appeared and they have reduced most of the CO2 to organic compounds, leaving an atmosphere where N2 is the most abundant component.

Hey there, I'm a rover planner for Curiosity (I drive, operate the arm, etc.). Very proud of the science team that did this work.
my non scientific take is life once existed on mars. not the kinda life - we think as similar here on earth but with it's own unique chemical composition - but however there was a planet wide extinction event.