Caught in the Cosmic Web – Dark Matter Structure Revealed by Hubble
Dark matter filament studied in 3D for the first time! NASA/ESA Hubblecast 58: “Caught in the Cosmic Web – Dark Matter Structure Revealed by Hubble Space Telescope”.
In this episode of the Hubblecast, Joe Liske (aka Dr J) shows how a team of astronomers has used Hubble and a battery of other telescopes to discover the secrets of massive galaxy cluster MACS J0717. They have found that an invisible filament of dark matter extends out of the cluster. This is our first direct glimpse of the shape of the scaffolding that gives the Universe its structure.
Astronomers using the NASA/ESA Hubble Space Telescope have studied a giant filament of dark matter in 3D for the first time. Extending 60 million light-years from one of the most massive galaxy clusters known, the filament is part of the cosmic web that constitutes the large-scale structure of the Universe, and is a leftover of the very first moments after the Big Bang. If the high mass measured for the filament is representative of the rest of the Universe, then these structures may contain more than half of all the mass in the Universe.
The theory of the Big Bang predicts that variations in the density of matter in the very first moments of the Universe led the bulk of the matter in the cosmos to condense into a web of tangled filaments. This view is supported by computer simulations of cosmic evolution, which suggest that the Universe is structured like a web, with long filaments that connect to each other at the locations of massive galaxy clusters. However, these filaments, although vast, are made mainly of dark matter, which is incredibly difficult to observe.
The first convincing identification of a section of one of these filaments was made earlier this year. Now a team of astronomers has gone further by probing a filament’s structure in three dimensions. Seeing a filament in 3D eliminates many of the pitfalls that come from studying the flat image of such a structure.