astronomy enters a new era

The embargo was strict. Only the people responsible for preparing the first images from the James Webb Space Telescope (JWST) had seen them. It was the President of the United States, Joe Biden, who unveiled the first on July 11. Four more followed the next day. ” I was overwhelmed with emotionadmits Laurence Tresse, astronomer at the Marseille Astrophysics Laboratory. Never had we seen the Deep Universe with such precision and such beauty. » « It’s a big relief to see that everything is working properly. adds Nicole Nesvadba, CNRS research director at the Lagrange laboratory of the Côte d’Azur Observatory.

Sent into space last December, the JWST is the successor to the Hubble Space Telescope (HST), which has been orbiting the Earth since 1990. The result of a partnership between the American, European and Canadian space agencies, it observes light in wavelengths ranging from orange to mid-infrared – while the HST observes at shorter wavelengths, in ultraviolet, visible and near infrared. ” This makes it possible to detect very distant galaxies and to penetrate to the heart of the dense clouds of gas and dust where most stars are born. “, points out Nicole Nesvadba. Its large mirror also offers better resolution in certain wavelengths.

Details never observed

Clusters of galaxies, stars that are born, others that die… Beyond the aesthetics, the images revealed give a glimpse of the diversity of the subjects that will be discussed, whether in our galaxy or in space. much deeper and farther. ” We are entering a new era of astronomy », says Nicole Nesvadba.

« By giving us access to sources and details of the Universe that we have never observed, JWST will allow us to solve scientific questions that we might not answer “says Laurence Tresse. For example, what phenomenon stops the formation of stars in the most massive distant galaxies when the Universe was younger? What sources of energy allowed the reionization of the Universe (see Landmarks) when it reached 1 billion years? Or what is the atmosphere of exoplanets made of (see interview)?

For now, scientists are hard at work. ” People have already started working like crazy, slips Laurence Tresse. We have our work cut out for the next twenty years. Especially since JWST got where it needed to go with low fuel consumption. There is therefore enough left to consider extending its lifespan beyond the minimum five years provided for, provided that the instruments hold up. ” It will work for at least ten years “says Laurence Tresse. ” Or even twenty ans “, hopes Nicole Nesvadba.