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Space Discussion Thread

diachi

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Apparently NASA will make a significant announcement today about something discovered by the Curiosity Rover on Mars. Any guess as to what it is? Fingers crossed for aliens. :p

https://www.nbcnews.com/mach/science/nasa-reveal-new-findings-its-mars-rover-curiosity-ncna880531



https://www.sciencealert.com/nasa-s-curiosity-rover-has-found-something-on-mars-here-s-what-you-need-to-know

"We found water where we haven't found it before", or something equally dull is my guess.
 



Ears and Eggs

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"We found water where we haven't found it before", or something equally dull is my guess.
Haha, yeah, will probably be very anticlimactic. Some boring rock that looks like it has had water flow over it more recently than we previously thought or something. :D
 
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RedCowboy

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Russia launched a Soyuz to the ISS yesterday, it's really something how these rocket launch videos have so few views compared to the new music video, whatever it is.


Note: The Soyuz MS-01 spacecraft is the first of a new series of Soyuz which has more modern computers weighing far less and taking up less physical space, as well as upgrades to it's solar arrays and docking system engines.

 
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H2Oxide

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Ears and Eggs

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I have to say, that was more interesting than I thought it might be.



https://www.nasa.gov/press-release/nasa-finds-ancient-organic-material-mysterious-methane-on-mars

https://www.cbsnews.com/news/nasa-mars-announcement-curiosity-rover-organic-matter-building-blocks-possible-life-today/



...it's really something how these rocket launch videos have so few views compared to the new music video, whatever it is....

Agreed that is one thing that I find so disappointing about this generation, many people are more interested in what some stupid celebrity did the other night while drunk than what is beneath the ice on Europa. Hoping some big space discoveries can maybe get the interest back again.
 
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paul1598419

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I saw a headline stating they found more evidence of life on Mars. Sounded like hyperbole to me. Didn't chase down the article and read it.

Finding methane and other nondescript organic molecules have been found in spectroscopic analysis of cloud masses in other galaxies and nebulae. Speculating about life causing these is just that. Rank speculation. I will be far more interested if/when they find some real evidence of life existing on Mars at some time in the past.
 
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diachi

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I saw a headline stating they found more evidence of life on Mars. Sounded like hyperbole to me. Didn't chase down the article and read it.

Finding methane and other nondescript organic molecules have been found in spectroscopic analysis of cloud masses in other galaxies and nebulae. Speculating about life causing these is just that. Rank speculation. I will be far more interested if/when they find some real evidence of life existing on Mars at some time in the past.
Yeah, people hear "organic" and immediately assume that means life. But really, any carbon containing molecule would fall under the "organic" category., even something as dull as methane.
 
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paul1598419

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Except for CO and CO2. Don't know why those aren't grouped with organic molecules, but when I took O Chem in college it was made clear that they are not. Carbon links with so many different atoms in so many different ways that organic molecules make up the greatest number of molecules around. Certainly don't need life to exist.
 

diachi

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Except for CO and CO2. Don't know why those aren't grouped with organic molecules, but when I took O Chem in college it was made clear that they are not. Carbon links with so many different atoms in so many different ways that organic molecules make up the greatest number of molecules around. Certainly don't need life to exist.

Generally speaking a compound is only considered organic when it contains both carbon and hydrogen, thus CO and CO2 aren't typically referred to as organic (same goes for any carbon compound that doesn't have any C-H bonds). Of course, an organic molecule can have other elements present, but they must contain a C-H bond too.

The presence of complex organic molecules is a good indicator of life, but it's far from definitive.
 
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H2Oxide

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Generally speaking a compound is only considered organic when it contains both carbon and hydrogen, thus CO and CO2 aren't typically referred to as organic (same goes for any carbon compound that doesn't have any C-H bonds). Of course, an organic molecule can have other elements present, but they must contain a C-H bond too.
I'm not a chemist, so take this with a grain of salt, but AFAIK the definition of "organic" is somewhat arbitrary and varies depending on context. For example, liquid PFCs are usually classified as "organic" even though they don't contain any hydrogen. Even stuff like Teflon is sometimes considered to be an "organic" polymer.
 
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Benm

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I am a chemist, and the distinction is not universally agreed upon: in science it matters mostly when you use something for and what kind of reactions you do to quality something as organic, inorganic, neither or both.

Things like CO2 are sometimes the product of biological processes, but also ones of totally anorganic ones like smelting metal out of ore.

Hopefully future mars missions drilling deeper can find what's actually been going on on that planet. If you find much more complex compounds that'd be a good indicator that mars had life at some point.

Something like the precense of CO2, methane and some simple sulfur compounds is by no means proof of life, though it could prove that Mars was able to be habitable to at least some basic life forms at some point.
 

paul1598419

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I'm not a chemist, so take this with a grain of salt, but AFAIK the definition of "organic" is somewhat arbitrary and varies depending on context. For example, liquid PFCs are usually classified as "organic" even though they don't contain any hydrogen. Even stuff like Teflon is sometimes considered to be an "organic" polymer.
I had thought so as well. I didn't major in chemistry, but I minored in it and there are many organic polymers that don't contain hydrogen. There are also many that do. I found the chemistry of plastics to be rather boring, but had to learn it all the same. These days I have to go and look at a chemistry text book to find the answer to a question. It is true what they say.....if you don't use it, you lose it.
 

diachi

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I had thought so as well. I didn't major in chemistry, but I minored in it and there are many organic polymers that don't contain hydrogen. There are also many that do. I found the chemistry of plastics to be rather boring, but had to learn it all the same. These days I have to go and look at a chemistry text book to find the answer to a question. It is true what they say.....if you don't use it, you lose it.
I'm not a chemist, so take this with a grain of salt, but AFAIK the definition of "organic" is somewhat arbitrary and varies depending on context. For example, liquid PFCs are usually classified as "organic" even though they don't contain any hydrogen. Even stuff like Teflon is sometimes considered to be an "organic" polymer.
I am a chemist, and the distinction is not universally agreed upon: in science it matters mostly when you use something for and what kind of reactions you do to quality something as organic, inorganic, neither or both.

Things like CO2 are sometimes the product of biological processes, but also ones of totally anorganic ones like smelting metal out of ore.

Hopefully future mars missions drilling deeper can find what's actually been going on on that planet. If you find much more complex compounds that'd be a good indicator that mars had life at some point.

Something like the precense of CO2, methane and some simple sulfur compounds is by no means proof of life, though it could prove that Mars was able to be habitable to at least some basic life forms at some point.

The most common definition of an organic compound is one which contains carbon bonded to hydrogen. But yes, it's not set in stone so the usage may differ. It depends on how you want to define it I guess. I hear "organic compound" and I usually jump to the definition I used earlier, molecules containing C-H bonds. In most cases that I've seen that's usually what's being referred to.

For the purpose of answering Paul's question about CO/CO2, the definition I used fits.

As described in detail below, any definition of organic compound that uses simple, broadly applicable criteria turns out to be unsatisfactory, to varying degrees. The modern, commonly accepted definition of organic compound essentially amounts to any carbon containing compound, excluding several classes of substances traditionally considered as 'inorganic'. However, the list of substances so excluded varies from author to author. Still, it is generally agreed upon that there are (at least) a few carbon containing compounds that should not be considered organic. For instance, almost all authorities would require the exclusion of alloys that contain carbon, including steel (which contains cementite, Fe3C), as well as other metal and semimetal carbides (including "ionic" carbides, e.g, Al4C3 and CaC2 and "covalent" carbides, e.g. B4C and SiC, and graphite intercalation compounds, e.g. KC8). Other compounds and materials that are considered 'inorganic' by most authorities include: metal carbonates, simple oxides (CO, CO2, and arguably, C3O2), the allotropes of carbon, cyanides excluding those containing an organic residue (e.g., KCN, (CN)2, BrCN, CNO−, etc.), and heavier analogs thereof (e.g., CP− 'cyaphide anion', CSe, COS; although CS2 'carbon disulfide' is often classed as an organic solvent). Halides of carbon without hydrogen (e.g., CF4 and CClF3), phosgene (COCl2), carboranes, metal carbonyls (e.g., nickel carbonyl), mellitic anhydride (C12O9), and other exotic oxocarbons are also considered inorganic by some authorities.

A slightly broader definition of organic compound includes all compounds bearing C-H or C-C bonds. This would still exclude urea. Moreover, this definition still leads to somewhat arbitrary divisions in sets of carbon-halogen compounds. For example, CF4 and CCl4 would be considered by this rule to be "inorganic", whereas CF3H and CHCl3 would be organic, though these compounds share many physical and chemical properties.
 
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paul1598419

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I believe that it is difficult to argue urea is inorganic. It was the first "organic" molecule that was synthesized having always come from urine before. That was a story I learned in my organic chem class. Also, many of the organic solvents used contain C bonds without H,. but they have always been referred to as organic solvents.
 

Benm

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When it comes to solvents, in chemistry the distinction in most cases is if it will mix with water or not. Things like methanol, ethanol, acetic acid and such are usually considered orgenic solvents as they are miscible with water in any ratio.

Something like benzene, ethyl ether, hexane etc are usually called inorganic. When you separate out fractions using a seporatory funnel you'd often just refer to the water layer and the inorganic layer, regardless of where any of the substance came from.

The better terminology here would be polar versus apolar, but in real lab conditions these things get up widely.

For astrochemistry you'd have to divide things up a bit further:

1 - generally available without any biological process (like water, or methane)
2 - uncommon without biological proces (like urea, fatty acids etc)
3 - almost certainly produced by some biological process (complex proteins, rna, dna, etc)

Category 2 is pretty broad though, depending on what you call 'uncommon'. One extreme example would be vitamin B12 - it is possible to synthesize that extremely complex module from the elements by chemistry without any enzymatic steps - i.e. it could be produced in a lifeless environment.

This synthesis takes over 70 steps and has an end yield of 0.01 percent or something like that, so i'd probably place detection of B12 as evidence of life, unless deliberately planted. For somehting like urea though, i would not consider it a sure sign of life. It takes only 2 very common substances (ammonia and carbon monoxide) and a bit of light to do it, which could easily happen on a lifeless world.
 




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