Methyl Bromide: New Study Suggests Absence of This Gas is Linked to Life on Other Planets

In a new study, researchers from the University of California Riverside recently suggested an idea that possibly never crossed the mind of most space aficionados that gas released from broccoli, as well as other plants, is one of the most signifying indications of the presence of life on a planet, including Earth.

The gas, methyl bromide in particular, has long been linked to life on Earth. It naturally occurs from the plant process defending itself, a ScienceAlert report said.

Methylation, as the defense process is identified, enables plants to expel foreign contaminants, like bromide, by attaching a series of carbon and hydrogen atoms to it, therefore gasifying it and enabling it to escape into the air.

Specifically, methyl bromide is interesting from an astrobiological viewpoint. It was used as a pesticide until the early 2000s and has a lot of essential advantages over other probable biosignatures if it appears in the atmosphere of an exoplanet.

A Hazardous Chemical

First, it has a comparatively short lifespan in the atmosphere of a planet. This is specifically essential for exoplanet searches as it means whatever process is producing the gas is most probably still accessible. Its existence is not simply an outcome of a geological occurrence that took place eons ago.

Another advantage, according to Universe Today where this report originally came out, is one that all astrobiologists want to see. There are very few nonbiological processes that generate gas, and even such processes are not usually natural.

Despite now being regarded as a hazardous chemical, methyl bromide was generated in large quantities for use as a pesticide prior to being regulated because of its deleterious health impacts.

Yet another benefit is the spectroscopic wavelength that it is sharing with a so-called "cousin gas" is a biosignature, as well, as methyl chloride, which is resulting from the methylation process, as well.

The atmosphere of Earth Detected

The combined signature would make them quite simpler to detect from far away, and both are indicative of the presence of a biological process, although being able to differentiate between the methyl bromide and methyl chloride, as methyl chloride has been seen around some stars, which was likely caused by an inorganic process.

It is not quite advantageous, but an interesting quirk about the ability to detect methyl bromide is that it would be somewhat difficult to detect the atmosphere of Earth from far away.

Its concentration levels are strong enough although the ultraviolet alright from Sun is causing water molecules in the atmosphere to split into compounds that take out methyl bromide, so it is not existing for a very long time, in the atmosphere of Earth.

An Opportunity to See Methyl Bromide in the Atmosphere

UV light is just an issue for Sun-like stars, nonetheless. Around stars like M-dwarfs, which are 10 times more typical in the galaxy compared to sun-like stars, there would be less UV radiation that would possibly break up the methyl-bromide molecule.

Since such M-dwarfs will be some of the first places astrobiologists are looking, they might be an opportunity to see a build-up of methyl bromide in their atmosphere.

As specified in a similar Lakannada report, any such detection might need to wait a little while, though. Even the JWST is not set up to detect trace elements in the atmosphere of an exoplanet.

Nonetheless, in the next couple of years, some ground-based telescopes will be up to the task. There's a need for hopeful astrobiologists to wait until after those come online before they can actually look for this very interesting biosignature.

Related information about methyl bromide is shown on Toxicology District's YouTube video below:

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