So, what did you do on your summer vacation?
An extraordinary extraterrestrial story popped into my inbox the other day from our resident astrochemist, Tony Remijan, here at the NRAO. He announced plaintively that a group of chemistry summer students had discovered one of the most important of Earth’s pre-biotic precursor molecules… floating out in space.
Cue raised eyebrows. “What?! Just like that?!”
“Well, no,” he explained, “They had to work wicked hard to identify it, but yeah, it was in the GBT’s public data archive waiting to be found, and baddaboom: Our understanding of the Universe is hosed. Cool, huh?”
OMG, yeah! Here’s their story:
These undergraduates, who all share a minority background like me, spent the past few months learning how to make and break molecules as a summer research experience made possible by the Virginia-North Carolina Alliance of the National Science Foundation’s Louis Stokes Alliance for Minority Participation program. They worked alongside University of Virginia graduate students and card-carrying PhD scientists, like Tony, at the UVa Chemistry lab under MacArthur Fellow “genius” Brooks Pate. (See http://www.virginia.edu/ccu/about.html for information on astrochemistry efforts at UVa.)
For every spectrum the budding astrochemists recorded from the CCU’s state-of-the-art gas-smasher apparatus, a hunt for that spectrum in our Green Bank Telescope’s (GBT) public data archive commenced. (Yes, that’s public data, data you can use for your own research.)
During one of their experiments, they took ammonia and methyl cyanide and blasted them apart in a closed chamber to make them recombine and possibly for new molecules. (It’s like dismantling two perfectly good Lego houses and using those Lego bricks to build new structures – in the dark.)
To figure out the new compounds they had made, the students charted the radio waves coming from the gas chamber. These waves carried the signature wiggles and jiggles of the new compounds, the fingerprints of the mystery molecules inside, as a spectrum of colors. The students learned from their mentors how to identify the common chemical fingerprints in their own spectra. Hooray!
To experience the “astro” in astrochemistry, the students then compared their lab spectra to data taken by the GBT tuned into the same wavelengths as it observed natural radio waves coming from space. The students confirmed a number of matching fingerprints to molecules that other researchers had already found in space before them. Hooray! However, they also saw some matches that were a mystery to everyone, including the card-carrying chemists.
Baffled, the diverse team looked to published papers on spectra at these frequencies until a suspect rose through the noise: the mystery signal could be coming from –gasp — a Holy Grail of compounds, cyanomethanamine [sigh-an-oh-meth-AN-uh-meen.] (I saw your lips moving.)
Cyanomethanamine is one of a few BFF relationships between two hydrogen cyanides (HCN), the golden Lego blocks of Life. When HCN pair up multiple times, they form the most important biological compounds you could name.
Go on, you can name them, I’ll wait.…that’s right: DNA, RNA, and ATP.
In other words, with partnerships of HCN molecules, you can assemble the most critical building blocks of life on Earth.
HCN was first discovered in space in 1970 at the NRAO’s 36 foot telescope in Arizona, now run by the Arizona Radio Observatory. HCN is common in space, and it has been found on the surfaces of other worlds, such as Jupiter and Titan, and on roving comets. It’s even been found in molecular clouds and star forming regions. So, it is no longer huge news to find HCN molecules out in space. What the group of summer students were contemplating was whether or not they’d found HCNHCN, a bonded pair of HCNs, floating in space. Identifying this so-called “dimer” of HCN would mean that these students had just spotted the Universe happily on its way to constructing a pile of prebiotic molecules.
A huge discovery such as that requires solid evidence…so the students were just not satisfied, they wanted one more piece of evidence to put that final nail in the coffin. – All data about its wiggles are from quantum mechanical calculations of what it should/could/would look like but the group didn’t have the equipment to find that last piece of evidence, the smoking gun, the shooter in the grassy knoll, etc…
Not a lot of folks realize that scientists are often compelled to invent their own equipment, or script their own software, to answer tantalizing questions such as this one. And they don’t work alone. Partnerships between engineers, ITers, and other scientists push the frontiers into which science grows. This discovery was no exception, and these students experienced in a summer what it is truly like to be a scientist on the cutting edge.
It took seven weeks of design and testing, but the young team with the talented graduate students in the Pate lab developed a new instrument that could smash gases in the desired frequencies that would duplicate the mystery spectrum. And when the mystery spectrum was finally isolated, the answer was awesome: it indeed matched the quantum signature of cyanomethanimine, an HCN dimer. “With this experiment, they are seriously on their way to a PhD and have found more molecules than many other researchers in the field…no joke,” Tony beamed.
Making cyanomethamine in a lab is, in itself, a chemistry achievement for any scientist, but truly remarkable for a group of students spending their summer learning the ropes. Finding cyanomethanimine in space? Yeah, they just pwned themselves.
Space is harsh. It’s an awful place to be, which is why I’m not typing from there. It’s so very, very, very cold, it’s always raining destructive, bond-breaking radiation from somewhere, and it’s basically a lonely expanse of not a whole lot of action. These should be all the wrong conditions for atoms to find and keep hold of each other.
And yet, Tony tells me, the students’ game-changing discovery demonstrates that atoms are hooking up routinely in space to make the most important compounds we could ever hope to find out there. The implications? Well, if even in the most inhospitable environments these Legos of Life can form, then the odds have greatly increased for finding biologically-rich worlds in our Galaxy and beyond.
“All of our best guesses about what the Universe can and cannot do are being blown away with these kinds of discoveries, and thanks to public data, even those folks who are new to the field are contributing to our enlightenment,” Tony said. “Being wrong about how awesome the Universe is? It’s the best part of my job, man.”