The télescope spatial James Webb, in place since the summer to observe the beginnings of the Universe and the atmosphere of distant planets, marked 2022 with exceptional images. Waiting for great discoveries in the years to come. Since its installation 1.5 million kilometers from Earth, the successor to the Hubble Space Telescope, itself still in operation, is already dazzling astronomers with images of unprecedented precision. Cherry on the cake, the precision of its launch allows it a lifespan of at least twenty years once morest a guaranteed minimum of ten.
“It is behaving better than expected from every point of view”, explains Massimo Stiavelli, head of the mission at the Space Telescope Science Institute, which controls the operation of the observatory: “The instruments are more efficient, the optics more precise and more stable”. An essential stability to obtain sharp images.
Images normally invisible to the naked eye
The general public also benefits, thanks to the colorization of the telescope’s output, the images of which are normally invisible to the naked eye. Unlike Hubble, which essentially observes the Universe in the visible spectrum (the one perceived by the human eye), the James Webb “sees” in the infrared. A radiance that every body, from the stars to the flowers, emits naturally.
At this wavelength, James Webb can detect the faintest gleams of the distant (and therefore old) Universe, pierce the veil of dust masking the star factory in a stellar nebula or even analyze with his spectrographs the atmosphere of exoplanets.
An operation of unprecedented complexity
The instrument’s first “tests for small rocky planets in the habitable zone, potentially similar to the Terreare spectacular,” says Lisa Kaltenegger, professor of astronomy at the American University of Cornell.
The flight of the James Webb aboard a rocket Ariane 5 end of 2021 crowned an odyssey begun by NASA more than thirty years ago. After several setbacks, ten billion dollars and the work of 10,000 people, the 6.2 tons of the telescope succeeded in an operation of unprecedented complexity.
It was on the way to its final position that the “Webb” deployed a sun visor the size of a tennis court. tennis, then the 6.5 meters in diameter of its main mirror. Once calibrated, with a precision of less than a millionth of a meter, the 18 petals of the mirror began to collect the light of the stars. On July 12, 2022, it delivered five images emblematic of its capabilities: a procession of thousands of galaxies, some of which date back to shortly following the Big Bang, 13.8 billion years ago, and a nursery of stars in the nebula of the Carina.
More recently, Jupiter appeared with a wealth of details, which will help to understand the inner workings of this gas giant.
“Excess” of galaxies
Audiences marvel at the shades of blue, red and gray offered by the image of the Pillars of Creation (gigantic columns of dust where stars are born). Scientists see it as a way to “revisit their models of star formation”, according to NASA. In the fifth month of its observations, astronomers have found the most distant galaxies ever observed, one of which existed only 350 million years following the Big bang. With a surprise: they appear much brighter than the theory predicted and might have formed earlier than expected.
“We have an excess of galaxies, compared to the models, in theUniverse distant”, reports to David Elbaz, scientific director of the astrophysics department at the French Alternative Energies and Atomic Energy Commission (CEA). Another surprise, when Hubble saw “essentially galaxies with irregular shapes, the precision of the James Webb makes them appear as magnificent spiral galaxies”, with a shape similar to ours. A kind of “universal model”, which is perhaps one of the keys to the formation of stars.
And a “profusion of small globular clusters”, populations of a few million stars, which might prove to be “a kind of missing link between the first stars and the first galaxies”.
In the area of exoplanets, we have obtained the first confirmation of the detection of carbon dioxide in the atmosphere of Wasp 39-b, with possible photochemical phenomena in its clouds. These first observations gave Massimo Stiavelli hope for “great things, not yet observed or yet revealed”.
