James Webb, the largest telescope ever to orbit, will be launched from Kourou, Guyana, at the end of 2021. It will allow the distant universe to be observed with unparalleled precision with the aim of learning more on galaxies, planets, stars and their formation.


It is a time machine that should shake up our knowledge of the universe.

James Webb, the largest telescope ever sent into space, will be able to observe the distant cosmos with its infrared vision, where the first galaxies were formed 13 billion years ago.

Equipped with a huge golden mirror, the telescope will be able to analyze the light emitted just after the Big Bang.

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A technological feat the "size of a tennis court"

This telescope should have been launched about 15 years ago, but it is so complex that there have been delays in manufacturing.

"You only realize your size when you are next to it, when you actually see it. Because you are not used to a satellite that is so big: its sun visor has the size of a tennis court. And we're going to send it all into space! "

describes Pierre Ferruit, from the European Space Agency (project partner with NASA and the Canadian Space Agency), who speaks of a technological feat.

At least ten years of infrared vision research

The telescope will be sent folded into space and will then take three weeks to fully deploy.

It will be put into orbit by the end of the year around the Sun, 1.5 million kilometers from Earth and will operate for at least 10 years.

It will succeed the Hubble telescope, operational since 1990, which already provided us with breathtaking images, but which had a limit: it did not go beyond the near infrared, while James Webb will carry out his observations of the 'orange of the visible spectrum at the middle infrared (from 0.6 to 28 micrometers against a limit of 2.5 for Hubble). 

The four main goals of James Webb

  • The search for the light of the first stars and galaxies that appeared in the universe after the Big Bang

  • The study of the formation of galaxies and their evolution, by comparing "the smallest and oldest galaxies to the large spirals and ellipticals of today, thus helping us to understand how galaxies assemble over the billions years, ”says the site.

  • Understanding the mechanisms of star formation: the telescope will be able to "see through and into massive clouds of dust that are opaque to visible light observatories like Hubble, where stars and planetary systems are born."

  • The study of planetary systems and the formation of life. "Perhaps he will even find the building blocks of life elsewhere in the universe. In addition to other planetary systems, Webb will also study objects from our own solar system," one can read on the site of James Webb.