A team of scientists using the National Science Foundation’s Robert C. Byrd Green Bank Telescope (GBT) has discovered two new molecules in an interstellar cloud near the center of the Milky Way Galaxy. This discovery is the GBT’s first detection of new molecules, and is already helping astronomers better understand the complex processes by which large molecules form in space.
The 8-atom molecule propenal and the 10-atom molecule propanal were detected in a large cloud of gas and dust some 26,000 light-years away in an area known as Sagittarius B2. Such clouds, often many light-years across, are the raw material from which new stars are formed.
“Though very rarefied by Earth standards, these interstellar clouds are the sites of complex chemical reactions that occur over hundreds-of-thousands or millions of years,” said Jan M. Hollis of the NASA Goddard Space Flight Center in Greenbelt, Md. “Over time, more and more complex molecules can be formed in these clouds. At present, however, there is no accepted theory addressing how interstellar molecules containing more than 5 atoms are formed.” […]
Complex molecules in space are of interest for many reasons, including their possible connection to the formation of biologically significant molecules on the early Earth. Complex molecules might have formed on the early Earth, or they might have first formed in interstellar clouds and been transported to the surface of the Earth.
Molecules with the aldehyde group are particularly interesting since several biologically significant molecules, including a family of sugar molecules, are aldehydes.
“The GBT can be used to fully explore the possibility that a significant amount of prebiotic chemistry may occur in space long before it occurs on a newly formed planet,” said Remijan. “Comets form from interstellar clouds and incessantly bombard a newly formed planet early in its history. Craters on our Moon attest to this. Thus, comets may be the delivery vehicles for organic molecules necessary for life to begin on a new planet.”
I find this pretty interesting, because the enzyme I work with catalyzes an aldehyde dehydrogenase reaction that uses propanal (aka propanaldehyde, aka proprionaldehyde). We use propanal to assay the enzyme’s activity, so I’ve got a big bottle of propanal sitting in the fridge. I kind of like the way it smells.
If you’re wondering what propanal is, think of its little brother, acetaldehyde, which contains two carbon atoms instead of three. Acetaldehyde is something that most of us have had the joy of communing with, given that it’s the main product of ethanol metabolism. When you drink, it’s actually the acetaldehyde, and not the alcohol itself, that gets you intoxicated. A second dehydrogenation turns acetaldehyde into acetic acid, aka vinegar, which gets digested as usual.