Nasa released this Tuesday, August 2, a rare and stunning image of a galaxy 500 million light-years away, the Cartwheel Galaxy, whose rings appear with hitherto unmatched clarity thanks to the brand new James Webb Space Telescope.
Two concentric rings
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.
A “sneak peek” of the “past” and the “future”
This galaxy had already been observed by the Hubble Space Telescope, but the infrared capabilities of James Webb reveal new details hitherto hidden, allowing to see through a large amount of dust.
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.
The Cartwheel galaxy is still in a state “transient”, NASA said in its press release. If the James Webb Telescope “provides us with a glimpse of (her) current state, it also gives us an idea of what has happened to her in the past, and how she will evolve in the future”.
A $10 billion engineering gem, the James Webb Telescope was launched into space about seven months ago, and is 1.5 million kilometers from Earth.