According to Dr Will Sutherland, of Oxford University, these 'lumps of hydrogen that do not shine' could hold the key to modern astronomy's greatest embarrassment. Despite massive telescopes built in exotic locations and expensive astronomical satellites launched into space, astronomers believe that the stars they can see account for only about a tenth of what is really out there. Most of the universe is missing.
The search for the missing matter has divided astronomers into 'Wimps' and 'Macho men'. The Wimps believe that for the most part the universe is composed of exotic subnuclear weakly interacting massive particles (Wimps).
Dr Sutherland and his colleagues are firmly in the Macho camp: they believe that the missing matter consists of reasonably conventional objects which are bigger than planets but smaller than stars, known as massive compact halo objects (Machos). Because they do not shine with their own light, they are invisible to astronomers' telescopes.
But on Friday Dr Sutherland will tell the European and National Astronomy meeting in Edinburgh that he and his colleagues have found evidence for Machos at the bulge in the middle of the Milky Way. They have used a computer to sift through the images of more than half a million stars, recorded by attaching a highly sophisticated television camera known as a charge-coupled device to the business end of the 1.25m Mount Stromlo telescope in Australia.
The group has already examined 8 million stars in our nearest neighbouring galaxy, the Large Magellanic Cloud, and found several candidate Machos. According to Dr Sutherland, they are about one hundred times bigger than Jupiter but about one tenth the mass of the Sun.