Gravitational Waves: Prevalence Across the Universe

[roineust]

Would it be correct to say, that gravitational waves of the magnitude that is currently detected by LIGO and similar detectors, are prevalent to the extent that there is no single location in the known universe, that such magnitude of gravitational waves, don't pass through at least several times a year?

 

[PeterDonis]

How would we know one way or the other?

 

[berkeman]

Would it be correct to say, that gravitational waves of the magnitude that is currently detected by LIGO and similar detectors, are prevalent to the extent that there is no single location in the known universe, that such magnitude of gravitational waves, don't pass through at least several times a year?

We are a single point in the Universe. How many events per year does LIGO report with high confidence?

 

[atyy]

LIGO lists its detections by year
https://www.ligo.caltech.edu/page/detection-companion-papers

https://www.ligo.caltech.edu/page/faq
"On average, over its first two observing runs, LIGO's detections have been made at a rate of one every 2 months, and this is before we reach so-called "design sensitivity" (which we expect to reach in 2020). The eleven confirmed detections made so far suggest that these kinds of events are relatively common. Once LIGO's detectors reach their maximum sensitivity, they could be detecting gravitational waves at a rate of one per week. The only way to refine the estimates of how often detectable gravitational waves pass, is to keep making detections! "

 

[snorkack]

More importantly, all known Ligo detections appear to come from distant extragalactic sources (like gamma ray bursts).
Since gravitational waves are not heavily attenuated either by distance or by passing through galaxies, only by inverse square spreading, we can guess that an observer in our general vicinity, but in an intergalactic void, would still see roughly the same number of gravitational wave events.
With just 11 confirmed detections, there is no statistical evidence for concentration in Milky Way disc or away from it, and no such concentration is expected.
Note that if most observed gravitational waves came from Milky Way, observers in intergalactic space would see less. But as stated, this is not the case.