NASA discovers the building blocks of life were forged in starlight
Ultraviolet light from stars crucial to formation of organic molecules needed to create life, study finds
All living organisms — from germs to jellyfish to human beings — are made of the same basic components. But where do those building blocks of life come from?
According to new revelations gleaned from data collected by a European Space Agency telescope, the answers may lie in the stars. Or, more specifically, in starlight.
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Astronomers studying data from the Herschel Space Observatory, now out of operation, have discovered that ultraviolet starlight may be the key to creating the fundamental molecules necessary for the formation of life — that is, carbon atoms connected to hydrogen, oxygen, nitrogen and other elements.
"The sun is the driving source of almost all the life on Earth. Now, we have learned that starlight drives the formation of chemicals that are precursors to chemicals that we need to make life," said Patrick Morris, lead author of the paper and researcher at the Infrared Processing and Analysis Center at Caltech in Pasadena, Calif., in a statement released by NASA's Jet Propulsion Laboratory.
The chemistry of the Orion Nebula
The researchers were looking at data collected from the Orion Nebula, a massive cloud of gas and dust some 1,300 light years away. Orion is the closest star-forming region to Earth that generates massive stars.
Specifically, they were observing organic molecules within Orion — carbon-hydrogen (CH) and its ionized, or charged, version (CH+).
Before now, it was theorized that CH and CH+ — the first organic molecules discovered in interstellar space — were the result of shock waves from so-called traumatic events, like exploding supernovae or young stars spitting out jets of gas.
The theory was that shock waves would cause the material they encountered to vibrate, and that those vibrations would knock electrons off atoms, leaving them ionized and more likely to bond together to form more complex molecules.
Life born from light, not shock
But data from Herschel shows no correlation between shock events and the presence of those molecules.
"These CH+ molecules were more likely created by the ultraviolet emission of very young stars in the Orion Nebula, which, compared to the sun, are hotter, far more massive and emit much more ultraviolet light," NASA explains.
"When a molecule absorbs a photon of light, it becomes 'excited' and has more energy to react with other particles. In the case of a hydrogen molecule, the hydrogen molecule vibrates, rotates faster or both when hit by an ultraviolet photon."
This excited hydrogen reacts with carbons that originally formed in stars to create CH+ and CH, the scientists conclude.
"This is the initiation of the whole carbon chemistry," John Pearson, a researcher at NASA's Jet Propulsion Laboratory and the study's co-author, said. "If you want to form anything more complicated, it goes through that pathway."