Scientists are proposing to bet on a gas produced, among other things, by broccoli, to search for life in the Universe. They see it as a potential biosignature.
And if to search for extraterrestrial life in the Universe, we were inspired by broccoli? It’s a very serious idea. It was advanced in The Astrophysical Journal, October 10, 2022. Scientists are interested in the gas emitted by this variety of cabbage. According to them, it could constitute an index of the presence of life on other planets.
Broccoli, as well as other types of plants and microorganisms, are capable of emitting gases to expel toxins, details the University of California at Riverside, in a press release presenting the study. This process is known as methylation: organisms add one carbon atom and three hydrogen atoms to another chemical element. In doing so, the toxins are changed into a gas that no longer poses a danger to the plant or microorganism.
It is this gas that scientists think we could seek to detect in the atmosphere of exoplanets, using telescopes. For them, it would be a promising sign of life. ” It is reasonable to assume that this basic metabolic process [la méthylation, ndlr] could evolve on habitable exoplanets “, write the authors. They add that one of these methyl gases, bromomethane (or methyl bromide), has advantages over other gases in the quest for life outside the solar system.
- It persists for a short time in the atmosphere: if it were found in the atmosphere of another planet, one would assume that it was produced not long ago.
- This gas is more likely to have been produced by biological processes (but neither can we completely rule out geological processes at its origin, such as volcanoes).
Where could we look for this gas in the Universe?
In the Earth’s atmosphere, bromomethane is difficult to detect, due to the intense ultraviolet light from the Sun. UV radiation from our star contributes to the destruction of this gas. However, on a planet orbiting another type of star, M dwarfs (smaller and colder than the Sun), it might be easier to spot this gas. In addition, M dwarfs are more than 10 times more common than stars like the Sun. These are good targets to search for potential life on exoplanets.
” In the coming decades, through a combination of ground-based and space-based telescopes, it will be possible to detect biosignatures of methylated gases “, conclude the authors of the study. It is nevertheless advisable to remain cautious: remember that this gas can also originate from non-biological processes. Detecting it would therefore not mean that life has been identified: it would still be necessary to explain what produced it, on the targeted exoplanet.
