The first images from the James Webb Space Telescope have kept all their promises, astounding the general public and the scientific community with their beauty and unrivaled level of detail. But what exactly do they show, and what do we hope to learn from them?
Southern Ring Nebula
Giant screens displaying images captured by the James Webb Space Telescope in Times Square on July 12, 2022 in New York City. Released one by one starting at 10:30 a.m. (2:30 p.m. GMT) from the Goddard Space Flight Center, the new images demonstrated the full power of the $10 billion observatory, which uses infrared cameras to peer into the distant universe. with unprecedented clarity. (Photo by Yuki IWAMURA / AFP)
One of James Webb’s goals is to study the formation and life cycle of stars, and for this, nebulae, gigantic clouds of gas and dust, are a prime target.
The Southern Ring Nebula surrounds a dying star. It is located about 2,000 light years away in our galaxy, the Milky Way.
“At the end of its life, with each pulsation, this star has expelled part of its material”, explained to AFP Pierre Ferruit, scientific co-manager of the telescope for the European Space Agency (ESA). “And what’s left in the center is the core of this star, which we call a white dwarf: a very small, very hot star.”
The orange rings around it represent the gas that was ejected from this central star. New stars could be born from it.
Another image of this same nebula, taken by James Webb at another wavelength, clearly revealed a second star in its center for the first time.
Carina Nebula
Also in the Milky Way, the Carina Nebula is a gigantic star-forming region, located about 7,600 light-years away.
The image is made up of “an area at the top which contains very little gas and dust, and one at the bottom with these breathtaking dust structures”, commented Pierre Ferruit. Some “very red” stars are also visible, “which are actually in the heart of the dust”.
The snapshot reveals hundreds of stars that have never been seen before, but also galaxies in the background, and structures still unknown.
The orange color comes from hydrocarbons, very large molecules, explained Klaus Pontoppidan, chief scientist for James Webb. “This could be the Universe’s way of transporting carbon (…) to habitable planets,” he said.
Stephan Quintet
Stephan’s Quintet is a compact grouping of galaxies, 290 million light-years away.
It includes five galaxies in total, four of which interact with each other, in a real cosmic dance. Two are merging.
Such observations should make it possible to learn more about how “galaxies collide and merge”, cosmologist John Mather, Nobel Prize in physics and one of the scientific fathers of James Webb, told AFP. Our own Milky Way “was probably assembled from a thousand little” galaxies, he noted.
The image also contains a black hole, which itself cannot be seen, but which can be guessed at by the material sucked up around it.
mistresses of galaxies
This very first snapshot unveiled includes nothing less than thousands of galaxies, some of which formed shortly after the Big Bang, more than 13 billion years ago. One of James Webb’s main missions is to explore the early ages of the Universe.
The galaxy cluster called SMACS 0723 is shown here as it was 4.6 billion years ago. But by acting as a magnifying glass, it also made it possible to reveal very distant cosmic objects behind it — an effect called gravitational lensing.
This is James Webb’s first “deep field”, that is to say an image taken with a long exposure time in order to detect the faintest gleams. Here, 12.5 hours. It only scratches the surface of the telescope’s capabilities in this area.
Exoplanet WASP-96b
Another main line of research for James Webb: exoplanets, that is to say a planet in orbit around a star other than our Sun.
This last image is not a photograph, but a spectrum, that is to say an analysis of the light emitted by an object, making it possible to determine its chemical composition.
WASP-96b is located 1,150 light-years away. It is a “hot Jupiter”, but with half the mass.
By observing the light passing through the atmosphere of this planet as it passes in front of its star, James Webb detected water molecules there. But also for the first time, clouds.
Next step: determining “the amount of water present, and the implications for the general composition” of its atmosphere, said Knicole Colon, an exoplanet specialist at NASA’s Goddard Space Center.
More than 5,000 exoplanets have been discovered since 1995, and scientists are searching for another world conducive to the development of life. (AFP)