The secret to the creation to life in our universe appears to be seeding – the proper elements in the right mix in the right places to form the right kind of molecules. Only then can these molecules evolve chemically into more and more complex structures, thus following a general pathway toward biology. The pathway for life as we know it starts with carbon, but one which is specific organized and structured.
Recently, a team of astronomers at the ALMA Observatory reported the discovery of this very element while probing distant galaxies. What they found was not just interstellar carbon, but a form of carbon with a branched structure. The discovery was made in the gaseous-star forming region known as Sagittarius B2 – a giant molecular cloud of gas and dust that is located about 390 light years from the center of the Milky Way.
Simple carbon chains aren’t particularly unusual in the cosmos, but complex carbon is a different matter. It is what the researchers, based at Cornell University and the Max Planck Institute, describe as finding a molecular needle in a cosmic haystack. The actual molecule in question is isopropyl cyanide, and it was discerned thanks to the miracle known as radio astronomy.
Within clouds of interstellar dust and gas, elements find themselves shielded from the harsh radiation of open space and are, thus, free to form into more complex arrangements. These molecules don’t just sit there, but instead move around within their cloud-homes and bump into each other. The result of this activity are radio signals which can be detected light-years away – in this case, by radio telescopes here on Earth.
Every molecule has a different radio signal, so it’s possible to pick apart the contents of interstellar junk by examining a cloud’s frequency spectra. NASA, via the Ames Research Center, even maintains a radio-emission frequency database to aid in the tracking of polycyclic aromatic hydrocarbons, a form of molecule thought to contain much of the universe’s carbon stockpiles.
The branching carbon structure of isopropyle cyanide is of particular interest because it’s thought that this arrangement is a step on the way to the production of amino acids, the building blocks of proteins, and hence organic life. The discovery gives weight to the increasingly popular notion that life, or at least many of the key steps leading toward life, actually occurs off-planet.
Life on Earth may have been well on its way while the planet was still just space dust waiting to come together into our rock-home. What’s more, the molecules discovered by the ALMA team probably aren’t alone. As the authors, led by astronomer Arnaud Belloche, wrote:
[Isopropyle cyanide’s] detection therefore bodes well for the presence in the [interstellar medium] (ISM) of amino acids, for which such side-chain structure is a key characteristic… This detection suggests that branched carbon-chain molecules may be generally abundant in the [interstellar medium].
The discovery follows a general progression in recent years adding more and more life-ingredients to our picture of the ISM. A 2011 study revealed that complex organic matter should be created in large volumes from stars, while a 2012 report study found that conditions within the ISM are uniquely suited to the creation of increasingly complex molecules, “step[s] along the path toward amino acids and nucleotides, the raw materials of proteins and DNA, respectively.”
Also in 2012, astronomers working for ALMA found basic sugar molecules hanging out in the gas cloud around IRAS 16293-2422 – a young star located some 400 light-years from Earth. The particular form, glycoaldehyde, is thought to be a key component of the reaction behind the creation of DNA. Indeed, more and more, the universe is looking less and less like a harsh environment in which life must struggle to emerge, to a life factory.