An enormous, spacetime-warping cluster of galaxies is the setting of immediately’s NASA/ESA Hubble Space Telescope picture. The galaxy cluster in query is Abell 209, positioned 2.8 billion light-years away within the constellation Cetus (the Whale).
This Hubble picture of Abell 209 exhibits greater than 100 galaxies, however there’s extra to this cluster than even Hubble’s discerning eye can see. Abell 209’s galaxies are separated by hundreds of thousands of light-years, and the seemingly empty house between the galaxies is crammed with sizzling, diffuse fuel that’s seen solely at X-ray wavelengths. An much more elusive occupant of this galaxy cluster is dark matter: a type of matter that doesn’t work together with gentle. Darkish matter doesn’t take up, mirror, or emit gentle, successfully making it invisible to us. Astronomers detect darkish matter by its gravitational affect on regular matter. Astronomers surmise that the universe is comprised of 5% regular matter, 25% darkish matter, and 70% darkish vitality.
Hubble observations, like those used to create this picture, may help astronomers reply basic questions on our universe, together with mysteries surrounding darkish matter and darkish vitality. These investigations leverage the immense mass of a galaxy cluster, which may bend the material of spacetime itself and create warped and magnified photos of background galaxies and stars in a course of referred to as gravitational lensing.
Whereas this picture lacks the dramatic rings that gravitational lensing can typically create, Abell 209 nonetheless exhibits delicate indicators of lensing at work, within the type of streaky, barely curved galaxies inside the cluster’s golden glow. By measuring the distortion of those galaxies, astronomers can map the distribution of mass inside the cluster, illuminating the underlying cloud of darkish matter. This data, which Hubble’s high-quality decision and delicate devices assist to offer, is vital for testing theories of how our universe developed.
Textual content Credit score: ESA/Hubble
Picture credit score: ESA/Hubble & NASA, M. Postman, P. Kelly