Gurmukh Singh: Is this dark matter I see before me?

An elusive dark matter particle may finally have been caught on film. The particle, with a mass, neutral charge and lifetime matching that of the so-called axion, has left its mark on a photographic plate.

The hypothetical axion was proposed more than 30 years ago and could make up dark matter. Earlier this year there were hints that an axion had been found, but that particle didn’t have the right properties to explain dark matter (New Scientist, 15 July, p 35).

Now Piyare Jain at the State University of …