James Webb Telescope to be launched into space on Saturday to scrutinize the origins of the universe

After a 30-year wait and after overcoming countless problems, the telescope James Webb, the largest and most powerful observation instrument ever built, will be launched this Saturday into space, where it will survey the origins of the universe and explore exoplanets similar to the Earth.

The take-off, postponed several times due to technical or meteorological problems, was confirmed for December 25 “in a launch window that begins at 12:20 GMT” and will last 32 minutes, indicated the NASA and the European Space Agency (ESA) this Wednesday.

The James Webb telescope will follow in the footsteps of the mythical Hubble, with the ambition to clarify two essential questions: “Where do we come from?” and “Are we alone in the universe?” Amber Straughn, a NASA astrophysicist, at a press conference in early December.

Conceived in 1989 and named “JWST” (James Webb Space Telescope, in honor of a former NASA leader), this telescope was designed in collaboration with the European Space Agency (ESA) and Canadian Cove Space Agency (CSA).

Its development was marked by myriad problems that delayed its launch for years and quadrupled initial costs to $ 10 billion.

The device was manufactured in the United States, and its launch will take place in Kourou, in French Guiana, aboard a ariane 5 rocket.

A revolution

“We are very excited, we have been waiting for this moment for a long time,” Pierre Ferruit, one of the scientists in charge of the telescope project at the ESA agency, told AFP.

For Ferruit, as for many other scientists and engineers, this mission represents a consecrated career achievement.

And the waiting list to access the observation schedules grows and the ESA agency has already received more than 1,000 applications for the first year of operation alone.

For the scientist this shows that “the issues for which the ‘Webb’ was conceived are still current, 20 years later”.

This unparalleled “generalist observatory”, both in size and complexity, is equipped with an immense mirror made up of 18 hexagonal segments. Its diameter is 6.5 meters, three times that of Hubble.

The mirror is of such magnitude that it had to be folded like an origami to be able to place it on the ship that will take it into space and once it has reached its destination, the operation to place it will be extremely delicate since its parasol is the size of a football field. tennis.

This “giant” will be located in the orbit of the Sun, about 1.5 km from Earth, far exceeding Hubble located “just” 600 km from our planet.

The location of the Webb, known as Lagrange 2, was carefully chosen. Its position allows “the Earth, the Sun and the Moon to be located on the same side of its parasol, which allows it to remain in the dark and in great cold”, explains Pierre Ferruit.

In this way, the telescope will be protected from any disturbance, an essential condition for its great mission: to track the invisible world of infrared rays, a spectrum that Hubble does not have access to.

A bumblebee on the moon

“It is so powerful that it is able to see a bumblebee from 380,000 km away, that is, the distance between the Earth and the Luna“explained cosmologist John Mather, one of the mission’s scientific fathers.

Scientists hope that JWST will be able to detect the faint light signals emitted by early galaxies. That happened at a gigantic distance, that is, a long, long time ago.

Hubble managed to observe the universe up to 500 million years after the Big Ban and its successor is expected to close the gap to about 200 million years, after the explosion that gave birth to the universe, 13.8 billion years ago.

This immense gap allows us to understand a mysterious period during which the universe came out of darkness. “We are missing some key paragraphs on this first chapter of the story,” analyzed astrophysics Amber Straughn.

The telescope could take an important step in exploring exoplanets orbiting other stars. So far there are about 5,000 registered and some are located in habitable areas, that is, neither very close nor very far from their respective suns.

But little is known about these bodies and the JWST should be able to determine their atmosphere to detect eventual molecules such as water vapor.

The ultimate goal is to know “if our Earth is unique or if there are similar planets” where conditions are conducive to the appearance of life, such as the presence of liquid water, explained Pierre Ferruit.


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