Discover the cosmos! Each day a different image or photograph of
our fascinating universe is featured, along with a brief
explanation written by a professional astronomer. 2000 October
31 Explanation: This haunting image from the orbiting Chandra
Observatory reveals the Perseus Cluster of Galaxies in x-rays,
photons with a thousand or more times the energy of visible
light. Three hundred twenty million light-years distant, the
Perseus Cluster contains thousands of galaxies, but none of them
are seen here. Instead of mere galaxies, a fifty million degree
cloud of intracluster gas, itself more massive than all the
cluster's galaxies combined, dominates the x-ray view. From this
angle, voids and bright knots in the x-ray hot gas cloud lend it
a very suggestive appearance. Like eyes in a skull, two dark
bubbles flank a bright central source of x-ray emission. A third
elongated bubble (at about 5 o'clock) forms a toothless mouth.
The bright x-ray source is likely a supermassive black hole at
the cluster centre wit