Five galaxies that seem to revolve around each other: this is the Hickson Compact Group 40 captured by Hubble. A billion years from now, they will collide to become one giant elliptical galaxy.
It’s one more year spent scanning the sky for the Hubble Space Telescope, who turns 32. For the occasion, NASA unveils a photo of the ” Hickson Compact Group 40 also called HCG40, a strange grouping of five galaxies. Among them, a galaxy called elliptical and an lenticular galaxy. As for the other three, they are in the form of spirals, like the Milky Way.
Located towards the constellation of the’hydrathe group is so compact that it would fit in a region of space that is less than twice the diameter of the stellar disk of our Milky Way. The cause ? The black matter : it surrounds the five galaxies in a sort of halo. As a result, they inexorably approach each other, moults by their mutual gravitational attraction, but also by that of the black matter, invisible. Hubble observed them at a key moment in their lives, as they prepare to merge with each other. Except that the time scales are not the same as for us, since the merger will only happen in a billion years!
It’s James-Webb’s turn to take over
Deployed in orbit around the Earth in 1990 by NASA astronauts, Hubble made more than 1.5 million observations of about 50,000 celestial objects! Enough to make great discoveries, such as that ofaccelerating expansion of the Universe, or the determination of its size and age. Today, James Webb is preparing to take over as it continues to calibrate and prepare all its measuring instruments. Just like its predecessor, it will scrutinize the deep Universe, with among all its objectives, that of studying the very first moments and the formation of galaxies. These could also be in the same state as the galaxies of HGC40, ie gathered in compact and dense clusters.
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