It has been a challenge for decades for scientists to try to imagine how the first organic molecules formed on the early Earth. Organic molecules are molecules made up of carbon, hydrogen, oxygen, nitrogen, and sometimes atoms of a few other elements. The molecules of life are organic, and so how such molecules first appeared on the surface of the Earth is important to understand the origins of life. Further, knowing how hard (or easy) it is to make organic molecules from scratch may indicate how common they are elsewhere in the universe—giving credible estimates on how common life might be out there.
While a number of scenarios have been proposed to explain the origin of organic molecules on Earth, most of them require significant quantities of energy, or conditions that don’t resemble those of the early Earth. Now, new research has found a process that produces a simple organic molecule under moderate conditions.
On the early Earth, the most common form of carbon was carbon dioxide, CO2. The problem with making organic molecules from CO2 is that, in order to move toward the molecules of life, it’s necessary to find a way to attach a hydrogen atom to the carbon (a perocess called “reduction”). Unfortunately, under most conditions, CO2 is quite resistant to reduction. Scientists Victor Sojo and Reuben Hudson of the University of the Atlantic managed to get CO2 to form bonds to a hydrogen atom under the known conditions found on the early Earth:
The researchers used their design to combine hydrogen with CO2 to produce an organic molecule called formic acid (HCOOH). This synthetic process resembles the only known CO2-fixation pathway that does not require a supply of energy overall, called the Wood-Ljungdahl acetyl-CoA pathway. In turn, this process resembles reactions that might have taken place in ancient oceanic hydrothermal vents.
The structure of formic acid is shown above, and you can see the bond between carbon and hydrogen at the bottom of the structure. It’s still a long way from formic acid and amino acids or nucleic acids, but it’s a start.
However, this reaction suggests another possible and timely use. Last year, I wrote another science diary about finding a way to chemically modify CO2 so that it can reenter chemical processes in reduced form, and thus taken out of the atmosphere, where it causes climate change. Well, here is another such reaction. So we get a possible path to the first complex organic molecules as well as a possible way to reduce the excess carbon dioxide in the atmosphere.
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From thesphynx:
joemog provides a delightfully pithy deconstruction of Supreme Court nominee Amy Coney Barrett's "originalist" hypocrisy. From Mark Sumner’s post on the nominee’s views on the illegitimacy of civil rights.
From elenacarlena:
I'd like to nominate JustinQ78's comment in the Bill Maher diary by Lefty Coaster. I think Bill Maher likes to stir up controversy. But controversy isn't going to win us the election if it means sniping at each other. Justin explains what we need to do instead.
From Youffraita:
learn has another great one, pretty much describing the vast conservative conspiracy that has helped bring us to this point, from Chitown Kev’s APR this morning. learn includes in the same comment thread a great transcript (plus link to the audio) of an interview given by our dear kossack friend Keef Knight.
From FindingMyVoice:
Quebecois' succinct comment in the front page diary, 'Uh oh, NY Times got Trump's tax returns' by kos, has been mentioned by several readers as TC-worthy. I agree!
"The next time some idiot tells me we need to run the government like a business, i am starting fires."
From cv lurking girlfriend:
This comment by lolsilently in HalBrown’s post on the brain-eating amoeba
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