Molecule Chirality Could Point to Alien Life

Over the recent years, an increased number of concepts referring to the “handedness of life” have begun to appear, and in areas of research few would have thought possible. For instance, astronomers are now working with scientists on the creation of a new means of looking for life on other planets, through the use of a tool that would basically determine if light coming in from other celestial bodies or moons is right- or left-handed. Experts at the National Institute of Standards and Technology (NIST) believe that this is one of the possibilities we, as a race, could follow in our quest to find life in other corners of the Universe.

The way in which molecular handedness, or chirality, will reveal the existence of life on other planets is not a direct one, experts warn. Rather, space-born instruments, flown in the vastness of space, will look for a specific chemical expression of existing molecules. These expressions vary considerably, even though the chemical structure of the molecules expressing them is the same.

That is to say, over the years, biologists have noticed that life favors a certain type of chirality over others. By detecting these subtle differences, astrobiologists and astrophysicists hope to be able to determine at least if a planet or moon is able to sustain life, and not necessarily if it already does so.

“You don’t want to limit yourself to looking for specific materials like oxygen that Earth creatures use, because that makes assumptions about what life is. But amino acids, sugars, DNA – each of these substances is either right- or left-handed in every living thing,” NIST Physicist Thom Germer, who leads his colleagues in the new line of research, explained. He added that the calculations that led to experts proposing chirality as the main target of future space exploration missions were very complex.

They feature a somewhat simplistic line of reasoning, but one that is of fool-proof logic. When life appears on a distant planet, the theory holds, the first organisms have a certain chirality. When they multiply, their offspring will also have the same chirality as their parents, and will pass it on to their offspring as well. As life evolves, and organisms multiply, the same chirality that the original inhabitants had will be kept throughout the generation, which means that a sensitive observatory could detect its signs from space, and assess the possibility of life existing on that specific moon or planet based on the readings.

“If the surface had just a collection of random chiral molecules, half would go left, half right. But life’s self-assembly means they all would go one way. It’s hard to imagine a planet’s surface exhibiting handedness without the presence of self assembly, which is an essential component of life,” Germer added, quoted by ScienceDaily. “We need to be sure we get a signal from our own planet before we can look at others. But what’s neat about the concept is that it is sensitive to something that comes from the process behind organic self-assembly, but not necessarily life as we know it.”