The Gravitational Wave Background

The amplitude of the gravitational wave background that we've detected is really at the upper limit of what we can model as come in from supermassive black hole binary systems. We have between a three sigma and a four sigma detection for sigma, which is like one in 10,000 chance that it's just noise That created this correlation across the pulsars. There are other possible astrophysical scenarios where all of the pulsars have this kind of noise. And so we have to be really careful when we're actually saying that we're seeing the gravitational waves.