The indispensable New Scientist reports that
the distribution of dark matter has been mapped in 3D for the first time, revealing how the mysterious substance has evolved over the lifetime of the universe. The results confirm that dark matter provided the scaffolding that allowed ordinary matter to clump together to form galaxies and clusters of galaxies.
They provide this interesting visualization: an evolution of the distribution of dark matter over time. It shows that the dark matter is, similar to other matter, getting “clumpier” over time:
An impressive video showing a 3D visualization of the distribution of dark matter over time is available in hi-res on the European information page for the Hubble Telescope: here. You can view it quickly below.
New Scientist also reports:
The behaviour of the Bullet cluster – the poster-child for the existence of dark matter – is provoking some cosmologists to propose that there might be a fifth fundamental force.
This hypothesis is based on preliminary calculations that a cluster of normal matter is accelerated by the presence of dark matter 20 percent more than expected based on the normal force of gravity. Skeptics abound and Occam’s razor is likely to prevail.