Unfolding the Universe's Dark Matter

Although the invisibility of dark matter makes it hard to detect, eluding scientists for decades, the team of astronomers led by Richard Massey of the California Institute of Technology has finally been able to achieve this, thanks to the of the Hubble COSMOS survey - the largest survey of the universe ever conducted by the Space Telescope.The map offers a first glimpse at the web-like large-scale distribution of dark matter in the Universe, like seeing a complex structure in daylight for the first time,for example a big city, with its suburbs and surrounding country roads. The map reveals a loose network of sponge-like structures of long filaments, intersecting in massive structures where clusters of galaxies are located.The COSMOS survey encompasses an area of the sky nine times that of the full Moon and was carried out by another international team of 70 astronomers led by Nick Scoville of Caltech.The map was created by using gravitational lensing techniques, which is the bending of star light caused by the presence of dark matter in the Universe, and analysing the distorted shapes of half a million distant galaxies. Such subtle distortions were then used to reconstruct the mass distribution along Hubble's line of sight.

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