JAMES WEBB. It was towards the planet Uranus that the space telescope turned its instruments in February. The snapshot published in April 2023 offers us a rare vision of the ice giant and its discreet rings.
[Mis à jour le 14 avril 2023 à 11h30] Launched in December 2021, the James Webb telescope has been scanning the Universe for almost a year from its observation point located 1.5 million kilometers from Earth. Using its infrared instruments, it provides us with new images of the most distant celestial objects every month. Galaxies, stars, nebulae or even exoplanets, nothing escapes his cameras. But the space telescope is also interested in the stars that surround us and evolve near our planet.
In February 2023, he aimed his instruments at one of the eight planets in the solar system. An icy giant, surrounded by rings less famous than those of Jupiter, it is the turn of the discreet Uranus to have its portrait drawn. There NASA unveiled a new image on which we can notably admire eleven of the thirteen rings of the planet rarely photographed, as well as a polar cap present on the surface of Uranus. According to the site from NASA, other observations of Uranus should be made by James Webb soon.
Month after month, the collection of photos from the space telescope is advancing rapidly. Since the first shot in July 2022, the images published by NASA have been more spectacular than each other. Using his state-of-the-art instruments, James Webb opens a window to the wonders of the cosmos in unparalleled quality:
What is James Webb’s orbit?
After its launch aboard an Ariane 5 rocket, the James Webb telescope has reached its final location after a month in space. It is now in orbit around the Lagrange 2 point. It therefore revolves around this location, but also around the Sun following the movement of the Earth. It is from this position that he makes his observations.
Why is James Webb at the Lagrange point?
After lift-off followed by a month-long journey, the James Webb Telescope placed itself in orbit around a point on the solar system which is called “Lagrange point L2”. This point is located in the alignment of the Sun and the Earth and allows the telescope to remain fixed with respect to these two objects. This point was chosen for its stability, thanks to which the telescope does not need to expend a lot of energy to maintain its position.
This location is also a way to keep the telescope instruments cool since it is located behind the Earth in relation to the Sun. However, this position is not enough to keep all of its tools at a sufficiently low temperature. This is why the telescope also has a huge visorsun to keep his instruments away from the heat.
What is the purpose of the James Webb Telescope?
The James Webb Telescope must fulfill various objectives during its mission, which will initially last 5 years, but which could be extended to 10 years. First, James Webb observes the first galaxies, which appeared just after the Big Bang. He will therefore go back in time to understand the formation of these structures and their diversity. The telescope also studies exoplanets and is more specifically interested in their atmosphere, in search of biosignatures, that is to say, signs of potential traces of life within the compounds of the atmospheres of the planets. Finally, he keeps an eye on an object much closer to us, the black hole Sagittarius A*, located at the center of our galaxy, the Milky Way. It should thus collect data which will supplement those of the network of telescopes which had produced the first image of this black hole in May 2022.
How does James Webb work?
A real gem of technology, the James Webb telescope is equipped with a huge mirror 6.5 meters in diameter which concentrates the light it receives. Four different instruments then capture this light ray and analyze it. These instruments are cameras and spectrometers, tools capable of detecting and analyzing infrared light, invisible to our eyes. It is thanks to this technology that the telescope can notably study distant galaxies formed shortly after the Big Bang.
These tools, however, require an extremely low ambient temperature to operate without the heat of its instruments or the environment distorting the results. The James Webb Telescope was therefore equipped accordingly. A tennis court sized sun shield has been designed to protect all measuring tools.
The unprecedented size of this telescope was a real headache to accommodate it in the fairing of the Ariane 5 rocket on board which it left Earth. The mirror is therefore composed of 18 foldable segments which are deployed once in space with remarkable precision.
What wavelength does the James Webb Telescope use?
The James Webb Telescope studies light in wavelengths ranging from 0.6 to 28 micrometers, that is, in the mid and near infrared. It is a part of the light that the human eye does not perceive but which makes it possible to detect very distant and cold objects like the first galaxies which formed just after the Big Bang.
How fast is James Webb?
James Webb is in orbit around Lagrange point 2, 1.5 million kilometers from Earth. It evolves around this point at a speed of about 1 kilometer per second. He thus completes the tour of the Lagrange point in 6 months. At the same time, the telescope accompanies the Earth in its movement around the Sun. It therefore completes a tour of the Sun in 365 days, like our planet.
What is the interest of the James Webb telescope compared to the Hubble telescope?
Hubble is an extremely powerful space telescope which has made it possible to discover a very large number of galaxies and to obtain completely new shots of many nebulae and other celestial objects. While it was only supposed to last ten years, Hubble continues, 30 years later, to send us spectacular images and to improve our knowledge of the Universe. “One of Hubble’s most enduring achievements is bringing the wonders of the universe to the general public,” said Kenneth Sembach, director of the Space Telescope Science Institute in the magazine. National Geographic.
Since the 90s, technologies have greatly evolved and the modern design of James Webb makes it an instrument with even greater ambitions than those of its predecessor. While Hubble is in orbit around the Earth, James Webb was positioned 1.5 million kilometers from our planet. Thanks to this positioning and its state-of-the-art instruments, it gains in precision and can observe even older objects. It can also provide details of structures discovered by Hubble, such as the nebula of the Hull photographed by Hubble then by the James Webb telescope.
From a technical point of view, the two space telescopes are without common measure. The James Webb Telescope is equipped with the largest mirror ever sent into space. With 6.5 meters in diameter, the latter is 3 times larger than that of Hubble. Its sun visor is also of unparalleled size since it measures 22 meters by 12, or 4 times the area of that of Hubble.
Who made the James Webb Telescope?
The James Webb telescope was manufactured by two American manufacturers: Northrop Grumman and Ball between 2009 and 2021. It was designed by three partner space agencies on the project: NASA (the American space agency), ESA (theeuropean space agency) as well as the CSA (the Canadian space agency). Each agency equipped the telescope with one or more instruments of its design. This is how France developed MIRI, one of the four instruments that will detect distant galaxies.
Who funded James Webb?
The final cost of the James Webb Telescope is up to the disproportionate ambitions of its mission. Estimated at the beginning of the project at approximately 500 million dollars, it will have finally cost 10 billion US dollars, which is equivalent to 9 billion euros. This colossal budget was partially supported by the Canadian agency and the European space agency.
Why is the telescope called James Webb?
The name of the telescope was chosen to pay tribute to a NASA administrator, James Edwin Webb. He occupied his functions between 1961 and 1968 during the Apollo program of the American agency which had the ambition to put a man on the Moon. His responsibility for the success of the program is widely accepted within NASA.