Why the success of the James Webb Telescope Hubble will revolutionize space observation

Astronomers have been talking about it for twenty years. After several delays and delays, the James Webb Telescope must be launched this Saturday, December 25, for an Ariane 5 rocket. Franceinfo explains why the new telescope exploded and reached বিল 10 billion (8, 9 billion euros) – funded by NASA, the European Space Agency and the Canadian Space Agency – to revolutionize space observation, whether to examine relatively close or very distant objects. Will happen.

Because it is the most powerful telescope sent into space

The James Webb Space Telescope (JWST), simply called the James Webb, is considered Like the jewels of space engineering. It is equipped with a large mirror consisting of 18 small hexagonal shaped mirrors. Once in space, the assembly must unfold like an origami, as shown in this video (In English).

When deployed, the JWST is 8 meters long, and its five-level-thick sunshade extends across a tennis court-sized area. “In general, processes like JWST are feared by space engineers. ” By That they fear they will block or they will open badly, comments CNRS astronomer franceinfo Olivier Bern. “There are a hundred of them there. It’s unprecedented and from that point of view it’s already a great mission. “Commented by someone who is also responsible for a scientific project by James Webb.

After all, JWST, which weighs 6 tons, is the most powerful telescope sent into space. Returning to the mirror, which makes it possible to measure the power of the telescope The Hubble, launched in 1990, is 2.4 meters wide, with JWST’s 6.5, as this NASA video explains. (In English).

Ideally, since James Webb’s mirror is larger than Hubble’s, it can capture more light and therefore see much more. What a good resolution.

“It’s one The gap Thanks to the technology that was acquired with the help of James Webb, a device never built before. “

Anthony Bokaletti, astronomer at the Mudon Observatory

at franceinfo

Unlike its cousins ​​on Earth, JWST will not be disturbed by the light and atmosphere of our planet: it is 1.5 million kilometers away from us at the second Lagrange Point (when Hubble is 570 kilometers above our heads in orbit)).

Because it will allow us to see the universe in a new way

“One of the scientific goals of JWST is to look at the light from the first constellation formed immediately after the Big Bang.Olivia Bern explains. We don’t really know how these first stars were formed, the heavy chemicals needed to enrich the universe. “He further said.

However, to be able to see such old and distant objects, it needs to be placed in infrared. In fact, the universe is expanding, the planets, galaxies are constantly moving away from us. With this distance, the light from this celestial object shifts to red, a phenomenon known in French as the “Doppler effect” (“Red transfer “ In English).

Designed to work in infrared, JWST will thus be able to explore the universe very deeply and observe very old objects formed for the first time 13.5 billion years ago (compared to 12.5 billion years for Hubble). In other words, we will be able to observe the universe at a very young age, since the Big Bang occurred about 13.7 billion years ago. Michelle Blank, Emeritus Emeritus Institute for Research in Astrophysics and Planetology, “Extraordinary breakthrough”.

“Although Hubble has captured observation in visible light and ultraviolet very well, James Webb works on infrared above all. It opens new doors.”

Michelle Blank, Astronomer

at franceinfo

To better understand the contribution of infrared, here is an example of what it allows compared to visible light. Among these The two photos were taken by Hubble and published via James Webb’s official Twitter accountIn the left image there is visible light. One on the right, in infrared light. We notice that, in the second, the visible objects are much larger and make it possible to see through the infrared dust.

And here’s a simulation of what James Webb might be able to do. The image on the left shows visible light, the image on the right gives an idea of ​​what JWST might create.

Working exclusively on infrared is nothing new. The Spitzer Telescope is special in this area. But James Webb is 1,000 times more powerful than the latter, according to NASA (In English).

There will be multiple responses to such detailed observations. Anthony Bokaletti, an astronomer at the Mudon Observatory (Hauts-de-Sain), told Franইনois Info if he was aware of the contents of the forthcoming discovery. “Sure” That JWST will be the source of significant progress in our knowledge.

“In many areas of astrophysics, there will be great advances for JWST.”

Anthony Bokaleti

at franceinfo

Because it will allow the rediscovery of already known heavenly objects

His ability to work in infrared allows James Webb to observe cold bodies, which is even more difficult to detect. This is what Thierry Fouchet from the Laboratory for Space Studies and Instrumentation in Astrophysics in Paris shows.

He is working on a project that paints a picture of the power of JWST. He will not point it to a distant object, but to our relatively near and cool: Jupiter, its ring, and its moons. By pushing James Webb’s equipment to its limits, he will study, among other things, the satellites of our largest planet in the solar system, such as Io, Ganymede and Callisto. Its purpose is to map the ice on its surface, to determine its age, its temperature, and the speed at which it reconstitutes.

Jupiter has four moons.  (NASA / NASA / AFP)

For the study of Jupiter, he admits he does not expect surprising innovations. “We’ll be more refined.” Our current knowledge, he admits. The discoveries are rather expected for satellites.

“I wouldn’t be surprised if anyone was surprised. We have very little information. What to expect is not clear and nothing has been firmly verified yet.”

Thierry Fouchet, Astrophysicist at the Paris Observatory

at franceinfo

Because it will help our exoplanets to know better

Since the discovery of the first planet outside our solar system in 1995, new discoveries have been made. Without it these often very distant stars are still unknown. “JWST will make it possible to observe them with unparalleled accuracy”Comment by Olivier Bernie, CNRS astronomer and scientific project manager for the telescope.

“We will be able to see inside the planetary system as if we were seeing ourselves. This is something particularly new.”

Olivier Barney, astrophysicist

at franceinfo

Astronomers will get accurate information about the structure of the exoplanet’s atmosphere, such as temperature, density. There will also be information on their presence or absence “Organic Molecules That Can Lead to Life”Astrophysicist notes.

Targeted exoplanets “Too young, too big and too hot. So they can’t support life or be livable.”Mood Anthony Boccaletti. “Discovering a habitable exoplanet and telling yourself that there is life elsewhere in the universe is the ultimate goal, but not much of what we’re going to observe with James Webb.”He added.

Because it opens the way to observe very few studied events

Nicole Nesvadba, an astrophysicist at the Observatory de la Cote d’Azur, is interested in supermassive black holes, which are found in the center of the galaxy and have between one million and several billion solar masses. If the first direct image of a supermassive black hole is released in 2019, “We know very little about this exceptional case“, He explained to Franceinfo.

This is the first image of a black hole.  It was produced as part of the International EHT Project and was unveiled on Wednesday, April 10, 2019.  (EHT collaboration)

According to him, JWST will probably “Revolutionary” To understand how supermassive black holes interact with their environment. This will allow you to observe “Details” A phenomenon that has not been studied “Seriously” Thanks to the Spitzer Telescope only once, about ten years ago, he explained.

With the help of JWST, researchers will be able to see in particular “Galactic wind” 3C326N produced by a supermassive black hole in the galaxy, about 1 billion light-years from Earth. In line of sight: Gases that are not observable from the soil. Their behavior could shed light on why they did not form this galaxy for ten billion years.

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