a goal that seems realistic

We will find life outside the solar system in less than 25 years“. This sentence was uttered on September 2, 2022 by Sascha Quanz, professor and astrophysicist, during the opening of the Center for the Origin and Proliferation of Life at the Swiss Federal Institute of Technology in Zurich (Switzerland). This statement stems directly from the progress that as space science has done over the past three decades.

Exoplanets like it was raining

The first observation of an exoplanet dates from 1995, just 27 years ago. Since then we have been able to list over 5,000, some of which, rocky, are located in the habitable zone of their parent star. These first properties imply a primary shared aspect with Earth. Moreover, according to astronomers, each of the 100 billion stars in the Milky Way would have at least one planet in its gravitational field.

This condition therefore implies excellent probabilities for the detection of a celestial body whose conditions would prove favorable for the development of any form of life. Note that here we voluntarily omit the wandering planets as well as those contained in the rest of the universe’s galaxies. Our telescopes remain too weak to unearth them because they are either located in total darkness or too far away. For example, the closest galaxy to us, Andromeda, is 2,500,000 light years away.

Credit: oorka/iStock

Atmospheric composition, an important indicator of a living presence

Thanks to the prowess of the James Webb Space Telescope (JWST), launched into Earth orbit on December 25, 2021, and the TESS project (for Transiting Exoplanet Survey Satellite) – a NASA telescope deployed in 2018 specifically designed to flush exoplanets out – , the number of known extrasolar objects is increasing day by day.

Experts have already shared a first photograph of a planet called HIP 65 426 b via James Webb. Besides, the latter revealed CO2 and water vapor in some of these remote atmospheres. Another planet whose surface could be covered in water, and located at “only” 100 light years was also discovered in the constellation Dragon in late August 2022.

Finally, last week, astronomers discovered two super-Earths, one of which one resides in the habitable zone of one’s star. It remains to be seen whether the star has an atmosphere, and if so, whether this atmosphere promotes or prevents the presence of liquid water.

TESS telescope
The TESS telescope. Credit: alejomiranda/iStock

A European program underlying such a discovery?

However, JWST was not primarily designed for this. New equipment is under construction and will allow them to focus all their energies on this research. ESA fitted a project called LIFE (Large Interferometer for Exoplanets), which has been awaiting funding since 2017. Its goals: unearths molecular signatures in the atmosphere of exoplanets, the origin of which would come from of living organisms.

JWST. Credit: dima_zel/iStock

We need to understand better the plausible building blocks of lifechemical reaction pathways and time scales and external conditions to help us prioritize target stars and planetsSascha Quantz added. “We have to check to what extent traces of life are true bioindicatorsfor there may be other processes which could lead to the creation of gas in these atmospheres“. However, the astrophysicist still expressed a slight reservation about the extraterrestrial findings: “There is no guarantee of success. But we learn other things along the way“.

We can therefore retain from all this rather encouraging perspectives, based on our constantly developing knowledge. Relating to the period of a quarter of a century stated by Sascha Quanz, this one does not seem today not as illusory as it seems. But only the future will tell us.

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