For the first time, scientists have found a complex organic molecule in deep space that is key to life on Earth. The molecule, propylene oxide, was detected in a giant cloud of gas and dust called Sagittarius B2, which is located near the center of the Milky Way galaxy about 25,000 light years away. It is a chiral molecule, meaning it exists in forms that mirror each other.
Chiral molecules are the backbone of human DNA
The discovery could help solve the mystery of how life began on Earth and probably elsewhere in the universe. Chirality is also called “handedness.” Just like a pair of human hands, chiral molecules are mirror-like versions of themselves. Most living things on Earth use only one version of molecules. For example, the ribose sugar in your DNA is only “right-handed.”
Molecules with “left-handed” and “right-handed” versions are essential for life as we know it. These molecules have already been detected in comets and meteors. Scientists presented their study at the American Astronomical Society’s meeting in San Diego. Findings of the study were published Tuesday in the journal Science. The discovery of propylene oxide in interstellar space supports the theory that chirality has cosmic origins.
How researchers detected propylene oxide 25,000 light year away
Brett McGuire of the National Radio Astronomy Observatory and co-author of the study, said in a statement that it would help us understand how prebiotic molecules are made in the universe. The findings also support the notion building blocks of life came to Earth from the outer space. Scientists used the Parkes radio telescope in Australia and the Green Bank Telescope in West Virginia to pinpoint the chemical details of the molecule in the center of our galaxy.
When molecules move around in deep space, they emit vibrations that are recorded as distinct radio waves. However, the signals linked to propylene oxide were not precise enough for astronomers to determine whether the molecules were “left-handed” or “right-handed.” Further studies on the interaction of polarized light with the molecules may offer clues whether one particular version of propylene oxide dominates the outer space.