One of science’s greatest mysteries is whether life exists outside of our planet and scientists are turning towards a distant relative of the cauliflower—broccoli—to help them find life in space. Broccoli, like many other plants, emits gases that help it expel toxins. These gases could help provide compelling evidence of life on other planets. This gas emitted by broccoli is the result of a process called methylation, where the organism adds a carbon atom and three hydrogen atoms to an unwanted chemical. This means that the potential toxin is turned into a gas that floats away safely into the atmosphere. Scientists believe that if such gases were detected in the atmosphere of another planet, they could suggest the existence of life there. Methylation is so widespread on Earth, we expect life anywhere else to perform it. Most cells have mechanisms for expelling harmful substances,” said Michaela Leung, a planetary scientist at the University of California Riverside, in a university press statement. Leung led a study on the subject published in The Astrophysical Journal. In the study, researchers propose that one such gas—methyl bromide—presents many advantages over other gases that are targeted in the search for life. One important advantage is that methyl bromide doesn’t remain in the atmosphere as long as some traditional “biosignature” gases. “If you find it, the odds are good it was made not so long ago — and that whatever made it is still producing it,” said Leung. The next advantage is that methyl bromide is more likely to have been made by something living than other biosignature gases like methane, which can also be produced by volcanoes and other geological processes. Also, methyl bromide absorbs light in a wavelength close to that of another biosignature gas, methyl bromide. According to the scientists, this makes both of them easier to find. Methyl bromide is fairly common on Earth but it is not easy to detect it in our atmosphere because of our Sun’s intense ultraviolet (UV) radiation. UV radiation causes chemical reactions that break up the water molecules in our atmosphere, splitting them into substances that destroy the methylated gas. The study proposes that methyl bromide would be more easily detectable around an M dwarf star than in solar systems like ours. These M dwarf stars have a just a fraction of our Sun’s mass and luminosity but are more than 10 times numerous, according to Scientific American. The lower luminosity means that they produce less of the kinds of UV radiation that can break up water in the atmosphere.
