
Space & PhysicsJuly 1, 1972
The X-Ray Sky
More than 120 celestial X-ray sources are now known; the list includes at least one neutron star, one quasar, two galaxies, one double source and perhaps even a black hole

The X-Ray Sky
More than 120 celestial X-ray sources are now known; the list includes at least one neutron star, one quasar, two galaxies, one double source and perhaps even a black hole