 But rotating neutron stars might be small enough to achieve the needed speed. Here's a system with two equal mass neutron stars that have reached the point where they are whirling around each other 10,000 times a second. The stars merge in a few milliseconds, sending out a burst of gravitational waves and a brief intense gamma ray burst. You can see the three phases, the in spiral, the coalescence or merger, and the ring down to an object, most likely a curved black hole, that is no longer asymmetric and therefore no longer radiating gravitational waves. If we fed the waveform into an audio generator, it would sound like this. We call it the chirp. The mass of a typical neutron star is 1.5 times the mass of the sun, with a radius of only 10 kilometers. If the system is 33,000 light years away, an average distance for a Milky Way object, it would give us a theoretically detectable wavelength and amplitude. But coalescing neutron stars are not common events. Mergers estimate that there might be one of these neutron star mergers every 50 years inside the Milky Way. To get a higher rate, we have to move outside the galaxy into the Virgo supercluster, our local supercluster that we covered in How Far Away Is It? video book. Within a 50 million light year radius, we expect to have as many as 10 or more neutron star mergers per year, because we're including thousands of galaxies. Unfortunately, at this extended distance, the amplitude drops to the 10 to the minus 21 range.