NASA announced on Friday the names of the first five cosmic targets chosen. But the images, which promise to be spectacular, have so far been jealously guarded in order to create suspense.
“These high-resolution images will show light from galaxies over 13 billion years old, formed shortly after the Big Bang,” Joe Biden spokeswoman Karine Jean-Pierre said Monday afternoon.
The American president must himself reveal the first scientific image taken by James Webb, during an event at the White House at 5.30 p.m. local time (2130 GMT), in the presence of the boss of the American space agency, Bill Nelson.
The latter had promised at the end of June that this surprise bag would contain “the deepest image ever taken of our Universe”.
An engineering jewel worth 10 billion dollars, James Webb has among his main missions the exploration of the first ages of the Universe.
The other images will then be revealed during a NASA online event on Tuesday morning. They must both impress the general public with their beauty and demonstrate to astronomers around the world the full power of onboard scientific instruments.
The experts will then be able to begin to interpret the data collected using dedicated software, giving the starting signal for a great scientific adventure.
“When I saw the images for the first time (…), I suddenly learned three new things about the Universe that I did not know before,” Dan Coe told AFP. one of the lucky few in the confidence. “It completely blew me away,” said this astronomer at the Space Telescope Science Institute in Baltimore, in charge of James Webb’s operations.
This telescope will “transform our understanding of the Universe”, he testified.
In colour
The first image expected on Monday could be of a deep field, that is, an image taken with a long exposure time to detect the faintest glows, according to a scientific source.
NASA announced on Friday that such a snapshot of the SMACS 0723 galaxy cluster would be taken. Acting like a magnifying glass, its particularity is to be able to reveal very distant objects located behind it — an effect called gravitational lensing.
The names of the other cosmic objects observed are just as poetic as they are spellbinding: the Carina Nebula and the Southern Ring (gigantic clouds of gas and dust where stars are formed), and Stephan’s Quintet (a grouping compact of galaxies).
The probably majestic colors that will be revealed in the photographs will not, however, be directly those observed by the telescope.
Light breaks down into different wavelengths, and James Webb works in infrared, which the human eye cannot perceive. Infrared colors will therefore be “translated” into visible colors.
Thanks to these observations in the near and mid-infrared, James Webb will be able to see through impenetrable clouds of dust for his predecessor, the mythical Hubble Space Telescope. Launched in 1990 and still in operation, it has a small infrared capacity but operates mainly in visible light and ultraviolet.
“Even when Hubble managed to take the image of a distant galaxy, it was not able to distinguish a squirrel from an elephant”, summarized for AFP David Elbaz, French astrophysicist.
Other big differences between the two telescopes: James Webb’s main mirror is almost three times larger than Hubble’s and it evolves much further: 1.5 million kilometers from Earth, against 600 km for Hubble.
Other worlds
Also to be released on Tuesday is the first James Webb Telescope spectroscopy, a technique used to determine the chemical composition of a distant object. In this case, WASP-96 b, a giant planet composed mainly of gas and located outside our solar system.
Exoplanets (planets orbiting a star other than our Sun) are also one of James Webb’s main areas of research. About 5,000 have been discovered since 1995, but they remain very mysterious.
The goal is to study their atmosphere to determine if some could turn out to be habitable worlds and conducive to the development of life.
The publication of these first images will mark the official start of the very first cycle of scientific observation of the telescope.
Several hundred observation projects, proposed by researchers from around the world, have already been selected by a committee of specialists for this first year of operation.