Evolution of structure in a void
see also this web page
Despite what their name implies, voids are not entirely empty.
Although the void regions do not contain large structures and massive galaxies,
they contain plenty of smaller-scale structure. This structure looks
very much like a scaled-down version of the large-scale web of filaments.
The movie illustrates the formation of this web
in the Cold Dark Matter model with dark
energy. The frames show the evolution of structures in a box of about
30 million parsecs. A spherical void is identified in the simulation
at the present-day epoch. The dark matter particles in this region are
then traced back in time to their initial positions. The movie
follows evolution of these particles over the entire history of the universe.
Note that because the density in the void is smaller than the average
density in the universe, the void is expanding rather than collapsing.
The structures appear to be flying away from each other on large scales.
On small scales, gravitational instability is still at work and leads
to the formation of interconnected web of filaments. At the final
epoch the void is rotated to highlight the three-dimensional geometry of
Questions and comments: Andrey Kravtsov (email@example.com)
You can use this material if you include the proper credit:
simulations and visualizations were performed at the Leibniz-Rechenzentrum
(Astrophysical Institute Potsdam)