[semaphoreP]

We've also been observing the universe using neutrinos (generated by the weak force). In fact, there have even been one neutrino event linked to a possible astrophysical source[1], but with less certainty than this gravitational wave/EM detection.

[1]: https://www.nasa.gov/feature/goddard/2016/nasas-fermi-telesc...

[pvg]

Supernovae neutrinos have been detected for 30 years, it's not just one event.