This galaxy had already been observed by the Hubble space telescope, but the infrared capacities of James Webb reveal new details so far hidden, allowing to see through a large amount of dust.
Le Monde with AFP
NASA published Tuesday August 2 a rare and superb image of a galaxy far from 500 million light years old, the galaxy of the carriage wheel, whose rings appear with a clarity so far unequaled thanks to the brand new James-Webb space telescope.
Like our Milky Way, astronomers think that the carriage wheel galaxy was in the past a spiral galaxy. But a spectacular event gave it its shape: the collision with another smaller galaxy (not visible on the image). Two rings then formed from the center of the collision, similar to the ripples in concentric circles caused by a pebble thrown into the water. This is what earned him his evocative name.
The first ring, more in the center, is very brilliant, and the second, outside, has been expanding for 440 million years. During its expansion, the ring hits the surrounding gas, triggering the formation of stars.
The carriage wheel galaxy is still in a “transient” state, said NASA in its press release. If the James-Webb telescope “provides us with an overview of [its] current state, it also gives us an idea of what has happened to it in the past, and how it will evolve in the future”.
Engineering jewelry
This galaxy had already been observed by the Hubble space telescope, but the infrared capacities of James-Webb reveal new details so far hidden, allowing to see through a large amount of dust. The composite image, resulting from the observations of two scientific instruments of the telescope, also has two other smaller galaxies, as well as many others in the background.
Engineering jewel with a value of $ 10 billion, the James-Webb telescope was launched from Kourou, French Guyana, last December. It is now 1.5 million kilometers from the earth.
Appointed in honor of James Edwin Webb, the second administrator of NASA (1961-1968), this telescope is approximately a hundred times more sensitive than its predecessor Hubble. Imagined by NASA from the launch of Hubble in 1990 and built from 2004, with the collaboration of European (ESA) and Canadian (CSA) space agencies, the James-Webb telescope is equipped with a 6.5-meter mirror Large, which gives it a surface and therefore a sensitivity seven times greater than its predecessor. Sufficient size to detect the thermal signature of a bumblebee on the moon.
Another difference with his predecessor: his observation mode. Where Hubble observes the space mainly in the field of visible light, James-Web vents in a wavelength escaping the eye: the near and medium infrared. A radiation that any body, star, human or flower naturally emits.
Its precision will allow you to better understand the formation of stars and galaxies and to observe exoplanets, whose astronomers always discover more specimens, to try to identify, perhaps one day, other planets housing the Life.