Chances of finding alien life just took a hit with space chemical discovery

2 Oct 2017

The antennas of the ALMA, set against the splendour of the Milky Way. Image: ESO/B Tafreshi (

Space biologists are a bit disappointed with the discovery of a chemical in space that was believed to be key in creating life.

Using the Rosetta spacecraft’s ROSINA instrument and data captured by the Atacama Large Millimeter/submillimeter Array (ALMA), a team of researchers has found the first evidence of the chemical compound Freon-40 in space.

Otherwise known as methyl chloride and chloromethane, the chemical was found around both Comet 67p in our own solar system and the infant star system IRAS 16293-2422, about 400 light years away from Earth.

This discovery makes it the first detection ever of a stable organohalogen – something that consists of halogens, such as chlorine and fluorine, bonded with carbon and sometimes other elements – in interstellar space.

Positives and negatives

Unfortunately for those on the hunt for extraterrestrial life, this adds some doubt to the theory that marked Freon-40 as a determining factor in the presence of living organisms, as the organohalogen discovery predates the origin of life itself.

The discovery of the compound in space was surprising to the researchers from the Harvard-Smithsonian Center for Astrophysics.

“We simply didn’t predict its formation and were surprised to find it in such significant concentrations,” said Edith Fayolle, the lead author of a paper now published in Nature Astronomy.

“It’s clear now that these molecules form readily in stellar nurseries, providing insights into the chemical evolution of planetary systems, including our own.”

A constituent of the ‘primordial soup’

However, speaking about the implications for finding life in the universe, co-author of the paper Karin Öberg is slightly more optimistic.

In her view, the discovery suggests that astronomers may have been looking at things the wrong way.

Instead of indicating the presence of existing life, organohalogens may be an important element in the little-understood chemistry involved in the origin of life.

“ALMA’s discovery of organohalogens in the interstellar medium also tells us something about the starting conditions for organic chemistry on planets. Such chemistry is an important step toward the origins of life,” she said.

“Based on our discovery, organohalogens are likely to be a constituent of the so-called ‘primordial soup’, both on the young Earth and on nascent rocky exoplanets.”

The discovery of Freon-40 also adds to the credence that because it is found in similar abundances in an infant star system and comet, a young planetary system could possibly inherit the chemical composition of its parent star-forming cloud.

This opens up the possibility that organohalogens could arrive on planets in young systems during planet formation or via comet impacts.

Updated, 5.24pm, 2 October: An earlier version of this article mistakenly suggested that the discovery of Freon-40 in space ruled the chemical out as an indicator of extraterrestrial life.

Colm Gorey was a senior journalist with Silicon Republic