SEARCHING space for exotic stars made entirely of free quarks is a tricky task, but now we know what to look for – a unique pattern of gamma-ray emissions given off by new quark stars as they cool. The signal should be detectable by the European Space Agency spacecraft Integral, due for launch this month.
When a star goes supernova, its core is thought to collapse so rapidly that the atomic nuclei within are squashed into a soup of neutrons. The process squashes material weighing as much as our Sun into a neutron star only 20 kilometres across. But theorists speculate…
