Scientists may have accelerated search for life on distant planets

6 January 2020, 20:06

Exoplanets could hold the key for discovering alien life
Exoplanets could hold the key for discovering alien life. Picture: PA
Nick Hardinges

By Nick Hardinges

Scientists have developed a new method for detecting oxygen in the atmosphere of distant planets which is vital for the prospect of life.

Researchers will now be able to use Nasa's James Webb Space Telescope to detect strong signals that oxygen molecules produce when they collide.

This signal could prove vital for helping scientists distinguish between living and non-living planets.

Despite exoplanets being too far away to travel to, their atmospheres may hold the key to discovering life in the universe.

Indications for life, otherwise known as biosignatures, can help scientists detect alien activity on distant, Earth-like bodies.

One of those key biosignatures is an atmosphere that contains oxygen.

A conceptual image of a water-bearing (left) planet and a dry planet (right), both with oxygen-rich atmospheres
A conceptual image of a water-bearing (left) planet and a dry planet (right), both with oxygen-rich atmospheres. Picture: PA / Nasa

Thomas Fauchez, of Nasa's Goddard Space Flight Centre, and lead author of the study, said: "Before our work, oxygen at similar levels as on Earth was thought to be undetectable with Webb.

"This oxygen signal is known since the early 1980s from Earth's atmospheric studies but has never been studied for exoplanet research."

University of California Riverside astrobiologist Edward Schwieterman helped develop the technique which was published in the monthly scientific journal Nature Astronomy.

Dr Schwieterman said: "Oxygen is one of the most exciting molecules to detect because of its link with life, but we don't know if life is the only cause of oxygen in an atmosphere.

"This technique will allow us to find oxygen in planets both living and dead."

Exoplanets with oxygen will not necessarily hold life
Exoplanets with oxygen will not necessarily hold life. Picture: PA

However, the Professor of Public Understanding of Science at the University of Brighton, Hal Sosabowski, told LBC News that we cannot get too carried away by the findings.

The Brighton Professor said this discovery was just "one step in a thousand marathons."

"It is significant, but right at the lower end of the spectrum because you need oxygen, hydrogen, water in the right format, fats, proteins and more for life to develop," he added.

"So, being able to potentially detect oxygen in a planet's atmosphere is one step closer in the right direction to discovering life, but it is the tiniest step."

The collision of oxygen molecules blocks parts of the infrared light spectrum from being seen by a telescope.

Researchers say that by examining patterns in that light, they can determine the composition of the planet's atmosphere.

However, an abundance of oxygen on an exoplanet does not necessarily point to proof of abundant life.

Another explanation could be that the planet is too close to its star and has instead experienced water loss through the evaporation of its oceans.