The James Webb telescope gets ready to search for other planets where there may be life

We only know of one planet Earth, but outside our Solar System there are countless stars that host exoplanets, and that the James Webb telescope will help to scrutinize with its powerful instruments.

It is one of the main missions of this gigantic apparatus that has needed three decades and close to 10 billion dollars to build. Its launch is scheduled for December 22.

Since the discovery of “51 Pegasi b” in 1995, scientists have discovered about 5,000 exoplanets.

For life to exist in one of them, as we know it, these exoplanets must not be too close or too far from the star in which they orbit.

Some of those space objects are gigantic gaseous masses, like Jupiter or Neptune, others are rocky, like Earth. They are all too far away to be observed directly, and also the ones that arouse the most interest, the rocky ones, are small and difficult to locate.

So far astronomers have only managed to detect them when they pass in front of their stars, since variations in luminosity occur.

With that observation they have barely been able to determine its size and density, but scientists cannot find out its atmospheric composition, or what happens on its surface.

‘See her insides’

That is the task of the Webb, which will display a masterpiece of astronomical technology: the Middle Infrared Instrument (MIRI), equipped with a camera and a spectrograph to detect that type of light emission that is invisible to the human eye.

“It will revolutionize the way we see the atmospheres of the planets. We will be able to see its insides! ” exclaims Pierre-Oliver Lagage, from the French space agency, who has worked at MIRI.

Pierre Ferruit, another project scientist Webb and member of the European Space Agency, explained that MIRI will be able to analyze the infrared trail that light leaves when it filters through the atmosphere of a planet, as it passes in front of its star.

In this way, Ferruit explained to AFP, scientists will be able to find out if that atmosphere contains molecules such as water vapor, carbon monoxide or methane.

Those three substances are present in Earth’s atmosphere and could potentially show biological activity on the surface of the exoplanet in question.

“Imagine that twenty years ago we barely knew exoplanets, and that now we will be able to know the composition of their atmospheres, that is enormous”Ferruit added.

“My dream would be to discover an atmosphere around a rocky planet in a habitable zone, with water molecules” explains René Doyon, from the Montreal Institute for Exoplanet Research, who is responsible for another instrument on board the Webb.

But that path is uncertain. Astronomers recently believed they had discovered phosphane, a gas associated with biological activity, on Venus. But analysis later showed that lead to be false.

Although the telescope Webb it will be able to detect biological molecules, knowing their origin will probably be “out of reach,” warns Doyon.

“For now we are looking for conditions favorable to life, such as the presence of liquid water”, indicates.

To begin with, the Webb It is already set up to examine the Trapista-1 planetary system, some 40 light-years from Earth.

That system has seven planets, seven of them in a habitable zone, near a dwarf star that is not excessively bright.

Webb it could provoke a new astronomical classification. “The discovery of exoplanets is full of surprises”warns Doyon.