The research will be vital to the success of future orbiting gamma-ray observatories. The crab nebula is a remnant of a supernova seen from Earth in 1054.
Astronomers know of only two in our Milky Way galaxy.
Many more of these remnants hide in the galaxy's dusty inner sections, where they can't be detected by visible light. This form of titanium has 22 neutrons, as opposed to the 24 in the titanium oxide in white interior house paint, for example. If you find a source of gamma rays in the sky at 1.157 MeV, you're looking at a 'recent' supernova remnant. Ernst Rehm of Argonne's Physics Division. Argonne National Laboratory photo by George Joch.