After years of waiting, the first image from the James Webb telescope was unveiled to the world on Monday, a sumptuous color shot showing galaxies formed shortly after the Big Bang, more than thirteen billion years ago. This first shot “quite spectacular also plays a role in the collective imagination of what the cosmos is”believes Olivier Berné, researcher at the CNRS, astrophysicist at the Institute for Research in Astrophysics and Planetology in Toulouse.
franceinfo: We see a lot of galaxies on this picture and we are talking in particular about these extremely old galaxies, 13 billion light years away and which therefore date back 13 billion years. What difference does it make to see these galaxies?
Olivier Berné: It changes several things. Overall, it changes a little our perception of the universe in which we live. These images really allow us to grasp the dimension and the depth of this universe. And then, it also allows us to probe the beginnings of this universe to try to understand what happened. One of the big challenges is trying to understand the nature of the first stars that formed in the universe. After the Big Bang, 13.8 billion years ago, the Universe did not contain stars, it is a period called the dark ages of the universe. And at some point, the first stars appeared, but we don’t know their nature. One of the challenges of the James Webb mission is to recover the light that comes from them to understand what they were made of.
What do we expect from these new photos?
We will have the first spectrum of an extrasolar planet, we will also have images of a region, the Carina Nebula: it is a nursery of stars. It is a place in our galaxy where stars and planets are forming. On the photos we currently have, it looks like a cloud of stellar dust. We will therefore see this cloud more deeply thanks to the images of James Webb and I think that these will be images which will obviously have a scientific interest, but which will also be quite spectacular and which, in my opinion, play a role in the imagination collective of what the cosmos is. And that is very important.
But will one day James Webb be able to take a picture of a planet outside the solar system? A real cliche.
Yes, there are projects called direct imaging of exoplanets, that is to say looking at a star and its planet next to it and trying to probe it as precisely as possible. Obviously, behind there is this question, are we alone in the universe? Are we going to be able to detect life with Webb? I’m one of the people who think it’s going to be difficult because we still have to progress, probably. But I think we will in any case have new information on the origins of life in the solar system, on Earth and also, more generally, in the universe. We will have new information about our origins and the origins of life thanks to James Webb.