This picture shows us further into the Universe than we've ever seen in X-ray light, revealing lots of very faint objects that previous images weren't able to detect. Almost three-quarters of the points of light in this picture are distant black holes, the others are galaxies. The colours tell us how energetic each object is: objects with the least energy are red and the most energetic are blue.
Credit:
NASA/CXC/Penn State/B.Luo et al.