NASA on Tuesday, August 2, released a rare and stunning image of a galaxy 500 million light-years away, the Cartwheel Galaxy, whose rings appear with unprecedented clarity thanks to the brand new telescope. James-Webb space.
Like our Milky Way, astronomers believe the Cartwheel Galaxy was once a spiral galaxy. But a spectacular event gave it its shape: the collision with another smaller galaxy (not visible in 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 it its evocative name.
The first ring, more in the center, is very bright, 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 Cartwheel galaxy is still in a state “transient”pointed out NASA in its press release. If the James-Webb telescope “provides us with insight into [son] current state, it also gives us an idea of what has happened to it in the past, and how it will develop in the future”.
This galaxy had already been observed by the Hubble Space Telescope, but James-Webb’s infrared capabilities are revealing new details hitherto hidden, allowing a large amount of dust to be seen through. The composite image, from observations by two scientific instruments of the telescope, also features two other smaller galaxies, as well as many others in the background.
A $10 billion engineering gem, the James-Webb Telescope was launched from Kourou, French Guiana last December. It is now 1.5 million kilometers from Earth.
Named in honor of James Edwin Webb, NASA’s second administrator (1961-1968), this telescope is about a hundred times more sensitive than its Hubble predecessor. Imagined by NASA from the launch of Hubble in 1990 and built from 2004, with the collaboration of the European (ESA) and Canadian (CSA) space agencies, the James-Webb telescope is equipped with a 6.5-meter mirror of scale, which gives it a surface and therefore a sensitivity seven times greater than its predecessor. A size large enough to detect the heat signature of a bumblebee on the Moon.
Another difference with its predecessor: its mode of observation. Where Hubble observes space mainly in the visible light domain, James-Webb ventures into a wavelength beyond the eye: the near and mid infrared. A radiation that any body, star, human or flower emits naturally.
Its precision will make it possible to better understand the formation of stars and galaxies and to observe exoplanets, of which astronomers are always discovering more specimens, in an attempt to identify, perhaps one day, other planets harboring life.