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Something already lost in the twisted passages of history is that the first generation of gravitational wave detectors was of an entirely different design than

Something already lost in the twisted passages of history is that the first generation of gravitational wave detectors was of an entirely different design than the current interferometers [1]. It never worked and Weber's claim to have detected gravitational waves from SN1987A in 1987, was widely discredited... [1] https://en.wikipedia.org/wiki/Weber_bar https://en.wikipedia.org/wiki/Weber_bar

jessriedel 2y ago
FYI, within the field, “first generation” now refers specifically to the first version of LIGO (not “advanced LIGO”). It’s not just that Weber bars didn’t work, it’s that they couldn’t work according to most physicists (but Weber obviously disagreed).
- openrisk 2y ago
  Umm, not sure what this clumsy attempt to rewrite science history is about? The internal nomenclature of those working within a particular approach cannot restart the clock of an entire field? Resonant bars were the first generation of gravitational wave detectors, period. > they couldn’t work according to most physicists That certainly requires a reference. There were several teams around the world besides Weber pursuing the approach. You make it sound as if the physics behind these bars was crackpot. Fyi, you may be confusing physicists with astronomers. The prevailing notion in astro circles was indeed that the known pathways to gravitational waves and with calculations made using GR would be too weak to be detected. (Incidentally astronomers were notoriously hostile to any GR research anyway. Why spend money in a high risk esoteric field if you can keep doing the same stuff over and over?) But a new observational window can always throw a surprise. A previously unknown class of sources may hit you in the face despite your primitive instrument. Historically this happened repeatedly with x-rays, radio etc. Or the theory you use to make predictions may be deficient and not telling you the whole story... In this respect Weber was simply unlucky. The universe is in a sense slightly more "conventional" and less exciting than it could have been.
  - bowsamic 2y ago
    > Resonant bars were the first generation of gravitational wave detectors, period. Well, too bad, no one in the field refers to it that way (I’m a LIGO member). Jess is pointing out how the language is used, not saying that it’s correct.
    - defrost 2y ago
      Last I checked David Blair's in the field, what with the sapphire clock development and his son being part of the 14 September 2015 first detection event. IIRC David talked about his niobium bar from 1976 as a first generation gravity wave detector - we certainly referred to it as a gravity wave detector in 1982 and it was talked about as such at the fifth Marcel Grossmann meeting. But hey, you're a LIGO member.
      - bowsamic 2y ago
        I’ve met David Blair and he’s not someone I’d want to associate with at all
        defrost 2y ago
        That's an interesting personal revelation that fails to address the question of whether or not he's in the field and whether the speakers on Gravitation at the fifth MGM in Perth consider his niobium resonant bar part of the generational development of gravity wave detectors.
      - jessriedel 2y ago
        Openrisk was commenting on how the language is used by practitioners in the field, for which being a LIGO member is directly relevant. It's a mistake to try and mock him for doing that. It just drives actual experts even further away from HN.
        defrost 2y ago
        My comment goes directly to how practitioners in the field refer to early gravitational detectors .. unless you're of the opinion that David Blair and son are somehow not practitioners in the field? Harrison's first Longitude clock that worked at global scale was H4 .. the fourth in the series. The LIGO detector came into being as a direct result of the work on earlier first generation detectors and technology invented there (eg saphire clocks) not only made LIGO possible but there are actual experts that straddle multiple generations of detectors. It's completely understandable that those that came later and have perhaps only worked with LIGO, count detector generations by LIGO editions. These are not, of course, the same as detector generations. It's likely a mistake to try and gatekeep others that are aware of the history, as noted that can just drive actual experts away.
awhitty 2y ago
Huh, I wonder if anyone's tried to validate this approach again now that we have LIGO (and presumably more precise equipment?). I know very little about the physics involved here, but the articles I found about Weber bars don't cite disagreement about the theory underpinning the experiment, so I'm curious if we expect a detectable effect with our current understanding? I also know very little about manufacturing Weber bars, but I could imagine it's cheaper to build 100s or 1000s of these and perform signal processing on them than building another LIGO. Or Weber bars in space? Just spitballing here
- sigmoid10 2y ago
  If you look at the lengths LIGO had to go to in order to eliminate background noise to even be able to theoretically detect gravitational waves, it seems very unlikely that a comparatively crude technology from the 80s could have achieved the same things. Like modern lasers or squeezed light states, which were mostly theoretical back then. If I remember correctly, Weber's device was claimed to show a huge amount of events per year, which would indicate tons of GW sources in our neighbourhood. LIGO and the rest of modern astronomy have since disproved that.
  - adolph 2y ago
    Sometimes noise turns out to be signal (see developments leading to Cosmic Microwave Background [0]). At this stage in gravitational wave detection is it well founded to consider noise as noise instead of information we cannot yet understand? 0. https://discovery.princeton.edu/2015/11/19/cosmic-background-51-years-ago-an-accidental-discovery-sparked-a-big-bang-in-astrophysics/ https://discovery.princeton.edu/2015/11/19/cosmic-background...
    - mr_mitm 2y ago
      Noise always has different sources, and when you eliminate noise you should always be conscious of the source. There should be a gravitational wave background analogous to the CMVB. Detecting it would be a sensation.

jessriedel 2y ago

FYI, within the field, “first generation” now refers specifically to the first version of LIGO (not “advanced LIGO”). It’s not just that Weber bars didn’t work, it’s that they couldn’t work according to most physicists (but Weber obviously disagreed).

openrisk 2y ago
Umm, not sure what this clumsy attempt to rewrite science history is about? The internal nomenclature of those working within a particular approach cannot restart the clock of an entire field? Resonant bars were the first generation of gravitational wave detectors, period. > they couldn’t work according to most physicists That certainly requires a reference. There were several teams around the world besides Weber pursuing the approach. You make it sound as if the physics behind these bars was crackpot. Fyi, you may be confusing physicists with astronomers. The prevailing notion in astro circles was indeed that the known pathways to gravitational waves and with calculations made using GR would be too weak to be detected. (Incidentally astronomers were notoriously hostile to any GR research anyway. Why spend money in a high risk esoteric field if you can keep doing the same stuff over and over?) But a new observational window can always throw a surprise. A previously unknown class of sources may hit you in the face despite your primitive instrument. Historically this happened repeatedly with x-rays, radio etc. Or the theory you use to make predictions may be deficient and not telling you the whole story... In this respect Weber was simply unlucky. The universe is in a sense slightly more "conventional" and less exciting than it could have been.
- bowsamic 2y ago
  > Resonant bars were the first generation of gravitational wave detectors, period. Well, too bad, no one in the field refers to it that way (I’m a LIGO member). Jess is pointing out how the language is used, not saying that it’s correct.
  - defrost 2y ago
    Last I checked David Blair's in the field, what with the sapphire clock development and his son being part of the 14 September 2015 first detection event. IIRC David talked about his niobium bar from 1976 as a first generation gravity wave detector - we certainly referred to it as a gravity wave detector in 1982 and it was talked about as such at the fifth Marcel Grossmann meeting. But hey, you're a LIGO member.
    - bowsamic 2y ago
      I’ve met David Blair and he’s not someone I’d want to associate with at all
      - defrost 2y ago
        That's an interesting personal revelation that fails to address the question of whether or not he's in the field and whether the speakers on Gravitation at the fifth MGM in Perth consider his niobium resonant bar part of the generational development of gravity wave detectors.
    - jessriedel 2y ago
      Openrisk was commenting on how the language is used by practitioners in the field, for which being a LIGO member is directly relevant. It's a mistake to try and mock him for doing that. It just drives actual experts even further away from HN.
      - defrost 2y ago
        My comment goes directly to how practitioners in the field refer to early gravitational detectors .. unless you're of the opinion that David Blair and son are somehow not practitioners in the field? Harrison's first Longitude clock that worked at global scale was H4 .. the fourth in the series. The LIGO detector came into being as a direct result of the work on earlier first generation detectors and technology invented there (eg saphire clocks) not only made LIGO possible but there are actual experts that straddle multiple generations of detectors. It's completely understandable that those that came later and have perhaps only worked with LIGO, count detector generations by LIGO editions. These are not, of course, the same as detector generations. It's likely a mistake to try and gatekeep others that are aware of the history, as noted that can just drive actual experts away.

awhitty 2y ago

Huh, I wonder if anyone's tried to validate this approach again now that we have LIGO (and presumably more precise equipment?). I know very little about the physics involved here, but the articles I found about Weber bars don't cite disagreement about the theory underpinning the experiment, so I'm curious if we expect a detectable effect with our current understanding? I also know very little about manufacturing Weber bars, but I could imagine it's cheaper to build 100s or 1000s of these and perform signal processing on them than building another LIGO. Or Weber bars in space? Just spitballing here

sigmoid10 2y ago
If you look at the lengths LIGO had to go to in order to eliminate background noise to even be able to theoretically detect gravitational waves, it seems very unlikely that a comparatively crude technology from the 80s could have achieved the same things. Like modern lasers or squeezed light states, which were mostly theoretical back then. If I remember correctly, Weber's device was claimed to show a huge amount of events per year, which would indicate tons of GW sources in our neighbourhood. LIGO and the rest of modern astronomy have since disproved that.
- adolph 2y ago
  Sometimes noise turns out to be signal (see developments leading to Cosmic Microwave Background [0]). At this stage in gravitational wave detection is it well founded to consider noise as noise instead of information we cannot yet understand? 0. https://discovery.princeton.edu/2015/11/19/cosmic-background-51-years-ago-an-accidental-discovery-sparked-a-big-bang-in-astrophysics/ https://discovery.princeton.edu/2015/11/19/cosmic-background...
  - mr_mitm 2y ago
    Noise always has different sources, and when you eliminate noise you should always be conscious of the source. There should be a gravitational wave background analogous to the CMVB. Detecting it would be a sensation.