4 ms·
Well, maybe they didn't. How would we ever know? The problem with LIGO is that is not making the expected number of discoveries, it has, as far as I know, one
by choeger 6y ago
Well, maybe they didn't. How would we ever know?
The problem with LIGO is that is not making the expected number of discoveries, it has, as far as I know, one signal that correlated to something visible with other means, and it is so expensive that there won't be independent confirmation soon.
Don't get me wrong, experiments like LIGO are massive achievements. But from an outsider point of view, that very scale and effort seems to be problematic when it comes to reproducing the results of experiments if there are no immediately useful predictions.
- lisper 6y ago> How would we ever know? That is why they built two of them in two different locations, one in Washington and one in Louisiana. Only results that are measured by both are considered actual signals.
- gameswithgo 6y agothere are a total of 4 now, I believe.
- lisper 6y agoWhere did you hear that? Wikipedia only knows of two. https://en.wikipedia.org/wiki/LIGO https://en.wikipedia.org/wiki/LIGO It would be really weird to build more than two because they are incredibly expensive and the incremental value of the third and fourth ones wouldn't be very high.
- roywiggins 6y agoWith several, wouldn't you be able to localize the waves to particular areas of the sky better? That would probably be useful. Expensive, but useful.
- magicalhippo 6y agoIndeed. See the light green (just LIGO) vs dark green (LIGO + Virgo) areas in this[1] picture. [1]: https://www.ligo.org/images/GW170817_images/GW170817-frontpg.png https://www.ligo.org/images/GW170817_images/GW170817-frontpg...
- formerly_proven 6y agoThere are more graviational wave detectors than just LIGO (2). There's at least GEO600, KAGRA and Virgo.
- ncallaway 6y ago> that very scale and effort seems to be problematic when it comes to reproducing the results of experiments First of all, LIGO is 2 observatories so every result out of LIGO was observed by at least two locations. There is also an independent project called Virgo which is making gravitational wave observations, and the results are being correlated with LIGO. They have made a number of overlapping observations, which further moves us towards reproducibility. Future observatories are also planned (like LISA), which will be another opportunity to further validate events.
- Strilanc 6y agoAdditionally, one of the gravitational wave observations was corroborated by immediate follow-up observations with normal telescopes [1]. [1]: https://www.as.arizona.edu/discovery-optical-counterpart-gravitational-wave-event https://www.as.arizona.edu/discovery-optical-counterpart-gra...
- caymanjim 6y agoI believe there have been visual/radio detections correlated with LIGO detections. I couldn't find a more authoritative source, but did find at least one reference in a Popular Mechanics[1] article. [1]: https://www.popularmechanics.com/space/deep-space/a28631/neutron-star-merger-gravitational-waves-fabric-of-space/ https://www.popularmechanics.com/space/deep-space/a28631/neu...
- ceejayoz 6y agoBetter source: https://www.ligo.caltech.edu/page/press-release-gw170817 https://www.ligo.caltech.edu/page/press-release-gw170817
- mhh__ 6y agoThis is in large part why we consider measurements probabilistically too. LIGO could be wrong, sure, but that's why it's measured twice. The results fit numerical predictions by general relativity that we think the probability of it being wrong is very low. It might not be, but we could be inside a Boltzmann brain too.