Dark Matter in a Simulated Universe

Explanation: Is our universe haunted? It might look that way on this dark matter map. The gravity of unseen dark matter is the leading explanation for why galaxies rotate so fast , why galaxies orbit clusters so fast , why gravitational lenses so strongly deflect light , and why visible matter is distributed as it is both in the local universe and on the cosmic microwave background . The featured image from the American Museum of Natural History s Hayden Planetarium Space Show Dark Universe highlights one example of how pervasive dark matter might haunt our universe. In this frame from a detailed computer simulation , complex filaments of dark matter, shown in black, are strewn about the universe like spider webs , while the relatively rare clumps of familiar baryon ic matter are colored orange. These simulations are good statistical matches to astronomical observations. In what is perhaps a scarier turn of events, dark matter -- although quite strange and in an unknown form -- is no longer thought to be the strangest source of gravity in the universe . That honor now falls to dark energy , a more uniform source of repulsive gravity that seems to now dominate the expansion of the entire universe.

Not only Halloween: Today is Dark Matter Day .