In pictures, in pictures. Star, galaxy, nebula … astrophysicists were asked to decipher images from the new James Webb Telescope

Submit every photo “Humanity has a view of the universe that we have never seen before.”. These words from Bill Nelson, head of NASA, sum up the value of the first images from the James Webb Space Telescope, which were revealed on Tuesday, July 12 with great fanfare. This post marks the beginning of the scientific operations of the most powerful space telescope ever built, which astronomers around the world have been waiting for for years.

But what exactly do we see in these beautiful images of stars and galaxies? To help you understand it, franceinfo asked astrophysicists Anthony Boccaletti and Eric Lagadec to decipher it. “These are things that have already been observed, but in a different way”Explains the first. “These pictures just serve to show that this machine has tremendous potential, it’s the beginning of a new era”second thought.

group of galaxies

The first image from the James Webb Telescope revealed on July 11, 2022, shows a cluster of galaxies.  (NASA/AFP)

The first shot, revealed by US President Joe Biden on Monday, shows a group of galaxies called SMACS 0723. “You have to imagine three different levels: the very bright stars, which form junctions, are in our galaxy. Then you see a massive group of galaxies that are white, and the orange objects are distorted images of distant galaxies”exhibits by Anthony Boccaletti, from the Paris Observatory.

Acting as a magnifying lens, the cluster of white galaxies makes it possible to detect very distant cosmic objects that lie behind them, an effect called a gravitational lensing. “The redder these galaxies are, the farther we are from them and the more we see them around the time of the Big Bang.”More than 13 billion years ago, Eric Lagadec adds. An astrophysicist from the Côte d’Azur Observatory uses an image to help us better understand these celestial bodies: “What we see is a part of the sky so small that it can be hidden by a grain of sand held at arm’s length.”. On Twitter, he also compared it to a previous image taken by the old Hubble Telescope, which makes it possible to realize the accuracy of James Webb.

Stephan quintet

Stefan Pentagram, in an image captured by the James Webb Space Telescope and revealed on July 12, 2022 (NASA/AFP)

Stephan’s Quintet is a compact assemblage of galaxies, 290 million light-years away. white bodies “Five interacting galaxies interact and dance around each other”Eric Lagadec explains. “This helps highlight star-forming regionsAnthony Boccaletti adds. What you see in red is the gas and dust that make up the stars.”.

Carina Nebula

The Carina Nebula, in an image from the James Webb Telescope unveiled July 12, 2022 (NASA / AFP)

This image shows what the star forming region looks like close up : a giant cloud of dust and gas. The Carina Nebula is located about 7,600 light-years away. It is cut into two parts. Below, an orange area where “We see gas, dust and stars forming‘, describes Eric Lagadec. At the top, there is a blue area, “Where we see stars are already formed, which radiate and create places without gas”. “Not all the colors you see here are real, the telescope sees bands that you can’t see with the naked eye, you have to interpret the light”continues Anthony Boccaletti, explaining that there are “A complete aesthetic work” behind.

a dying star

The Southern Ring Nebula, in two images captured by the James Webb Telescope, was revealed on July 12, 2022 (NASA)

These two images, taken with two different instruments from the James Webb Telescope, show the Southern Ring Nebula, which surrounds two stars, one of which is dying. “When a star dies, it spews out gas and dust, that’s what we see in this image.”Eric Lagadec decrypts. nebula structure, In the form of Dipoloimplying the presence of a second, smaller star, which can be seen in the visualization to the right.

Spectrum of an exoplanet

Spectrum of exoplanet WASP-96B, recorded by the James Webb Telescope.  (European Space Agency)

This is the least exciting picture of this first rendition, and for good reason: It’s a spectrum, an analysis of the light emitted by an object to determine its chemical composition. In this case, the extrasolar planet – that is, a planet outside our solar system – WASP-96 b. “By observing its main star, we were able to detect a slight modification of the light when the planet passes in front of it and this allows us to obtain information about the composition of its atmosphere.”Anthony Boccaletti explains. However, the astrophysicist wants to dampen the excitement that can arise about the mention of “water” (water) in this graph: this water is not in liquid form but gaseous, which does not have the same potential at all. In terms of life develop.

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