Friday, September 26, 2008

Mothballs In Space!

Detection of naphthalene in the Interstellar Medium
Image Credit: Gabriel Pérez, Multimedia Service/

Although we refer to outer space as a "vacuum," it isn't really empty. There are atoms and gas molecules flying around, although they are rare (generally just a few atoms per cubic centimeter, whereas our atmosphere has about 2 x 1019, or 200 million trillion atoms per cubic centimeter). The gas and molecules we find between stars is called the interstellar medium, or ISM.

Around the sun, the ISM is pretty thin, and mostly made of individual atoms. But around the stellar nurseries where new stars are being formed, the ISM gets pretty thick. Not as thick as Earth's atmosphere, but thick enough that atoms are likely to bond together to make molecules. Simple molecules, like carbon monoxide (one carbon atom and one oxygen atom) , have been known for many years. But recently, astronomers have begun to find more and more complex molecules, including alcohol and even amino acids (the building blocks of proteins, and so important ingredients for life)!

This morning, the Astrophysical Institute of the Canary Islands and McDonald Observatory announced the discovery of naphthalene, one of the most complex molecules ever seen in space, in the ISM in a star-forming region in the constellation Perseus.

Since so many complex molecules have been found in the ISM, it may not seem exceptionally newsworthy to add another to the list. But, like amino acids, naphthalene is a molecule that is useful for life. The presence of naphthalene and amino acids in space means that many of the complex chemicals needed for life are actually quite common in the Universe. Any new planets forming around the baby stars in this part of the sky will have a nice supply of organic molecules incorporated into them. Given just the right conditions, perhaps life could even form. As the astronomers involved in this work are continuing to look for even more complex organic molecules, don't be surprised to hear of similar discoveries in the coming years.

When I heard the announcement of the discovery of naphthalene, the first thing I thought of was mothballs. Naphthalene is the main active ingredients in mothballs. And that got me to thinking, maybe the naphthalene is not native to the ISM. Maybe aliens in Perseus have seen the movie "Starship Troopers" and, not knowing it was just a movie, have decided to protect themselves with giant floating mothballs. Or, perhaps, Starship Troopers is real, and we'd better get to work building our own space-borne mothballs. Or maybe not.

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