Ghost in the Machine
](http://oldblog.atomic-temporary-53335355.wpcomstaging.com/wp-content/uploads/2007/04/Dark%20Matter%20and%20the%20Bullet%20Cluster.jpg "Dark Matter and theâ¦
The image above shows the Bullet Cluster. Also known as 1E 0657-56, this is a pair of clusters of galaxies some 3.4 billion light years away. As Jon Davies told us in yesterdayâs Astrolunch meeting however: you should be careful about believing everything you see. This image is not a regular photograph by any means. You can see the galaxies scattered about with an orange glow. This much is familiar. Layered onto this optical data is the pink, X-Ray picture from the Chandra telescope. This pink light is actually the high energy X-Ray radiation from a hot gas that permeates the cluster. Again though it is not unusual to see two different wavelength regimes seen in the same photograph.