A new study reports the first detection of chiral molecules in space, paving the way to understanding why chirality is "biased" on Earth. Our planet is home to a puzzle involving chiral molecules, those that, despite being mirror images of each other, don't exactly match; imagine a left-handed and right-handled glove, for example. They aren't interchangeable. Life on Earth is made of groups of such molecules that overwhelmingly share just one type of handedness, a phenomenon known as homochirality. The amino acids that make up the proteins in our bodies, for example, are all left-handed. To date, the source of this chiral bias on Earth has been a mystery, though some suggest insights might be found in space since it's thought that interstellar clouds contain the raw ingredients for the formation of our solar system. However, a chiral molecule has never been found in space. Now, Brett McGuire, P. Brandon Carroll and colleagues have used radio waves to detect a chiral molecule called propylene oxide in Sagittarius B2 North, a cloud of gas and dust roughly three million times the mass of the Sun and located in the center of our Milky Way galaxy. Chiral molecules of propylene oxide were detected in the cold, outer area of Sagittarius B2 North, rather than in the hot cores within the gas cloud. These results demonstrate the existence of an important new class of molecules in space. What's more, the discovery is an important first step in understanding if chirality in space can explain homochirality on Earth.
The Milky Way and Galactic Center rise over Lake Waiau on the summit of Mauna Kea. This material relates to a paper that appeared in the June 17, 2016, issue of Science, published by AAAS. The paper, by B.A. McGuire at National Radio Astronomy Observatory in Charlottesville, Va., and colleagues was titled, "Discovery of the interstellar chiral molecule propylene oxide (CH3CHCH2O)." Credit: Photo by Brett A. McGuire. Foreground: P. Brandon Carroll
source: American Association for the Advancement of Science