'Weird' Molecule Detected on Titan Has Never Been Found in Any Atmosphere

[Judi Lynn]

MICHELLE STARR
28 OCTOBER 2020

Titan, the already pretty weird moon of Saturn, just got a little bit weirder. Astronomers have detected cyclopropenylidene (C3H2) in its atmosphere - an extremely rare carbon-based molecule that's so reactive, it can only exist on Earth in laboratory conditions.

In fact, it's so rare that it has never before been detected in an atmosphere, in the Solar System or elsewhere. The only other place it can remain stable is the cold void of interstellar space. But it may be a building block for more complex organic molecules that could one day lead to life.

"We think of Titan as a real-life laboratory where we can see similar chemistry to that of ancient Earth when life was taking hold here," said astrobiologist Melissa Trainer of NASA's Goddard Space Flight Center, one of the chief scientists set to investigate the moon in the upcoming Dragonfly mission launching in 2027.

"We'll be looking for bigger molecules than C3H2, but we need to know what's happening in the atmosphere to understand the chemical reactions that lead complex organic molecules to form and rain down to the surface."

More:
https://www.sciencealert.com/scientists-have-just-found-a-really-bizarre-molecule-in-titan-s-atmosphere

[JohnnyRingo]

1. I love this stuff.

Good read.
Thanx for posting

[littlemissmartypants]

2. Thanks! ❤ nt

[Mike Nelson]

3. I think...

... the large moons around the gas giants (like Saturn) are more likely to have life, or could be seeded. Titan and a few others may be much more Earth-like than Mars or Venus.

[SheltieLover]

4. Ty for posting this!

Fascinating!

[eppur_se_muova]

5. "Weird" is an understatement. This molecule is what is termed a 'reactive intermediate' on Earth.

Last edited Sun Nov 8, 2020, 05:09 PM - Edit history (1)

One of the carbons in the ring is bonded to only two other atoms -- an example of a carbene, almost all of which are very highly reactive. There are however, a number of highly substituted stabilized carbenes, including mesomerically stabilized carbenes, of which cyclopropylidene is an example -- the unsaturated, three-membered ring is stabilized by aromatic resonance, being essentially a cyclopropenium cation minus a proton; a lone pair of electrons occupies the position where the proton would otherwise be. (Cycloprepenylidene has its own wiki page, which does not discuss mesomerism or aromaticity.)

The obvious source of cyclopropenylidene is reaction of atomic carbon with acetylene high in Titan's atmosphere; atomic carbon is known to occur in the solar wind, and acetylene has been detected in Titan's atmosphere.

Particularly at higher temperatures, the highly reactive, strained cyclopropylidene should rearrange to its isomer 1,2-propadiene, or allene, which has been detected previously in Titan's atmosphere. It is only the cryogenic conditions of Titan's atmosphere which allow it to persist there.