Que nous révèlent les premières images du télescope spatial James-Webb ?

Que nous révèlent les premières images du télescope spatial James-Webb ?

Six months after liftoff, already in orbit 1.5 million kilometers from Earth, the James-Webb telescope is working perfectly. The proof began to send us images of the cosmos with an unprecedented level of detail. Here are three of them as told by three astrophysicists.

1galaxy cluster SMAC 0723

This is the first image revealed by James-Webb. It was unveiled by US President Joe Biden on July 12, 2022, as at the height of the Apollo program in the 1960s. And it is already one of the most famous images in our universe.

This photo is “a deep field“, explains Nicole Nesvadba, astrophysicist and director of research at the CNRS. “Orn point the telescope to a part of the sky where there are no particularly bright objects in order to detect which ones are fainter in that part of the sky“. The result, then, is this photo in which thousands of galaxies appear, some so far away that they look like a small red dot in the background.

It is these barely visible elements that are of particular interest to scientists. These are some of the oldest galaxies in the universe, formed more than 13.3 billion years ago. “In astronomy, the farther out into the universe you look, the further back in time you go.Nicole recalls. Nesvadba. And James Webb, thanks to these powers of seeing in the infrared, a light invisible to our eyes, makes it possible to go further back than any other telescope before him.

twoCarina Nebula

The James-Webb Telescope is just one big time machine. It is also an instrument to analyze the chemical composition of objects. In particular to understand the formation of stars like our sun.

Here we are in our galaxy, the Milky Way, about 7,500 light-years away. from the earth. And this is a nebula, also called a star nursery. “At the top, with this blue background, we are in an area where the gas is very hot”explains Olivier Berné, astrophysicist at the Research Institute for Astrophysics and Planetology in Toulouse and director of the science program for the James-Webb Space Telescope. He chases: “Towards the bottom, we see these orange nebulosities. These are called interstellar clouds. They are made up of gas and dust. Inside these clouds, where it’s cold enough and gravity is strong enough, clouds of gas and dust can collapse and form new stars. You can also see stars forming in some places.“.

Note that we can see a nebula with the naked eye in our sky. This is the Orion Nebula, located 1,500 light-years from Earth.

3Jupiter and its moon Europa

James Webb’s infrared sight is also beginning to scan objects in our solar system. A first photo of Jupiter was published on July 14.

In this image we see Jupiter and one of its four moons called Europa“, describes Tristan Guillot, astrophysicist at the Côte d’Azur Observatory and specialist in the formation of gas giants”.Thanks to James Webb, we look at Jupiter at high resolution in the infrared, so we look at the heat that the planet is emitting, which will tell us a lot about its composition. We’ll also be able to study this big red spot on the right. It’s an anticyclone that’s been there for 300 years that we don’t know much about,” rejoices Tristan Guillot.

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