See the two bright dots at the center of the picture? The dot on the right is a neutron star, a tiny body only a few miles across, but with the mass of 1.4 suns. The resulting dense object is believed to be 10 billion times stronger than steel. The neutron star spins about 30 times a second, releasing a pulse of energy that researchers can detect. The pulsing was first detected in 1968, and led to the study of a new class of astronomical objects called pulsars.