The building blocks of life are abundant in our universe. Organic, life-forming chemicals are common in giant molecular clouds throughout deep space. The fact that life arose here on Earth is testament to the fact that other places will harbor it, too. It seems apparent that complex and self-replicating living systems exist elsewhere on the planets of moons of other solar systems yet to be detected.
Dense molecular clouds have been identified in deep space. Located 6,500 light-years away, the majestic Eagle Nebula or M16-the now famous "Pillars of Creation" photographed by NASA's Hubble Space Telescope in the 1990s-contains over 1 million atoms per cubic inch.
(Aside: If you examine the photograph of the Pillars of Creation pictured in the online Wikipedia article titled "Eagle Nebula", our solar system, if added to the image for scale, would appear as a dot smaller than the period at the end of this sentence. The pillars are 2-3 light years long!)
While the term "dense" is used loosely here, astronomers consider dense molecular clouds to be the breeding grounds for the chemicals of life.
While the guts of the Eagle Nebula may be extremely cold, such a high vacuum environment does not get in the way of producing life's building blocks and other things.
Inside the nebula, ice particles act like Velcro when it comes to atoms and molecules. They sweep up debris and, in turn, are exposed to intense ultraviolet radiation from young stars awakening within parts of the cloud; ice particles are a medium for highly reactive chemical events.
Eventually, large molecules accumulate in the cloud as gravity helps collapse the molecules into vast protoplanetary disks. Then a rain of organic compounds contributes to the mounting inventory of life-forming materials. As the rain progresses the rate of organic synthesis skyrockets. This is exactly the way our solar system formed; on Earth the organic rain met the right conditions and then life arose, emerging first from deep inside our planet's crust.
How do we know organic molecules abound in stellar objects such as the Eagle Nebula? The science of radio astronomy is essential in understanding the inner workings of these vast clouds.
Each type of organic molecule absorbs a particular wavelength in the electromagnetic spectrum. Radio telescopes on Earth measure the E.M. waves coming from distant stars located on the far side of the nebula.
As the distant starlight passes through the clouds, astronomers know that certain diagnostic wavelengths will be weaker in the background, others stronger in the foreground.
At my old stomping grounds,the NASA Ames Research Center, astrochemist Dr. Louis Allamandola created experimental conditions akin to those inside the Eagle Nebula.
First, Allamandola chilled a vacuum chamber to very low temperatures.
Next, he introduced a spray of gases found in molecular clouds-diatomic and triatomic chemical species such as hydrogen, carbon dioxide, carbon monoxide and water. Finally, he passed a beam of UV radiation into the chamber and examined the spectrum of the chemicals produced by the reaction with UV radiation.
The resulting reactions produced large molecules such as nitriles (carbon and nitrogen) and ethers (hydrocarbons linked to oxygen including alcohol, etc.). Some amino acids were detected, too, compounds very similar to the building blocks of living cellular membranes.
What's in the Sky: Want to search for M16, the Eagle Nebula? You'll need a reliable telescope and a dark sky. According to European astronomers Hartmut Frommert and Christine Kronberg, "M16 is found rather easily either by locating the star Gamma Scuti, a white giant star of magnitude 4.70. From Altair (Alpha Aquilae) via Delta and Lambda Aql.; M16 is about 2.5 degrees (19 min. in R.A.) west of this star. M16 and the Eagle Nebula are best seen with low powers in telescopes."
Lou Varricchio, M.Sc., was a science writer at the NASA Ames Research Center in Mountain View, Calif. He is currently a member of the NASA-JPL Solar System Ambassador program in Vermont. In 2009, he received the U.S. Civil Air Patrol's Gen. Charles E. 'Chuck' Yeager Aerospace Education Achievement Award.