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New catalog of 90 gravitational wave detections published

The scientists operating the world’s three gravitational wave detectors today released a new catalog of all their detections, totaling 90 with 35 never before published.

All signals come from merging black holes and neutron stars. The new catalog contains some surprises, such as an unusual neutron-star–black-hole merger, a massive black hole merger, and binary black holes revealing information about their spins.

…The researchers have also published two papers accompanying their new catalog today. One looks at what the events can tell us about the population of compact objects in our Universe, how often they merge, and how their masses are distributed. In the other paper the researchers employed the gravitational waves to better understand the expansion history of the cosmos by measuring the Hubble constant.

Because of the tiny sample so far detected, these generalized results cannot be taken too seriously, though they do give hints at the larger context.

All three observatories are now undergoing upgrades, and will resume operations in a few weeks.

Genesis cover

On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.

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  • Col Beausabre

    “Because of the tiny sample so far detected, these generalized results cannot be taken too seriously”

    This reminds me of a complaint that my father had regarding junior engineers under his management, late in his career. Dad, of course, had been educated using the slide rule (I still have his K&E Log-Log-Decitrig that he bought in 1939 when he began his sophomore year at Texas A&M). The youngsters had been brought up on calculators and computers. While Dad appreciated these developments (although occasionally he and his contemporaries would whip out the trusty old slip stick that had been their faithful friend by years) he felt it led to a serious retrogression in the engineering profession. The younger generation had no knowledge of significant figures. They would generate reports with suspiciously precise numbers – the Spurious Digit Effect

    “Spurious digits, introduced by calculations resulting in a number with a greater precision than the precision of the used data in the calculations, or in a measurement reported to a greater precision than the measurement resolution.”

    So you multiply numbers , say 15.13 and 4.56 and report the result as 68.9928. That may be mathematically correct, but impossible practically. You can’t be more precise than your inputs. Here they have two digit input precision, so the result can’t have four digit precision. Applying significant figures, the reported result should be 68.99

    Dad wasn’t so much concerned with the figures – he’d tell the reports’ authors to rewrite applying significant figures – but with the underlying attitude. That we can be so precise in our calculations. He used to joke that he’d make a calculation, add an appropriate safety factor, then double it. He could see people pressing the state of the art based on the impression of precision and that would lead to problems, maybe disasters

  • wayne

    Col Beausabre-
    Great story with an excellent point.
    We had someone like that when I was in grad school, he always liked to calculate answers to the 4th decimal place, ‘because it was more accurate.” (we were dealing with lever-presses from white rats, it was a binary thing, ya’ know, but he loved “being accurate.”)

    My g-father was a Civil Engineer during the Depression and to make extra money he often submitted small articles to Popular Science / Popular Mechanics and the like. (trying to track these down has been a chore, most were unattributed.)
    One of his more interesting projects was writing a 10 page instruction manual (on spec) for a slide-rule manufacturer. They paid him $35 (and a free slide-rule.) Still have that somewhere although I don’t recall the name.
    I do have a number of K&E slide-rules and a variety of very cool Drafting instruments (mainly Dietzgen). I am embarrassed to say however, I have no idea how to work a slide-rule, and my drafting skills are less-than-neat. I can however read blue-prints, even though they aren’t actually blue anymore.

  • I think that my high-school class was the last one in that school, to get formal instruction on the use of slide rules. By the time I hit senior year, I had my first calculator – a TI SR-50.

    Though what has driven home the importance of significant figures, is writing test reports for approval – you don’t give the approvers any more digits than necessary to meet the spec, lest they question whether you actually met the spec or not if you are on the edge.

  • George C

    I used my trusty 6 inch plastic slide rule when I took the FCC 1st class commercial license test. There was only one other person taking the test that morning, at the FCC office in Washington DC. He had one of the first HP programmable calculators. Adjusted for inflation $3200. There were quite a few multiple choice questions with answers like 2.3, 2.4, 2.5, 2.6. I was done first and got my tested graded and passed. The other person was still messing with his calculator.

  • wayne

    Jester / George —
    Great back-stories!

    total tangent– have a “Victor MEC/2” calculator my dad bought (circa 1975-ish? He was a Land Surveyor.) The only thing it did was the regular 4 functions, percent, and memory add/subtract. Cost like’ $500. Later on he upgraded to the TI programable with the surveying-library modules.

  • wayne

    (sorta) back to gravitational waves…..

    extremely interesting back-n-forth on “science.”

    Dave Rubin Interviews Brian Keating

    partial show-notes:
    “Brian answers the basic question of what is science? He explains why scientific literacy has been replaced by combining religion and science. He discusses how the scientific process is about rigorous data gathering and why the questioning of “experts” is vital to scientific progress. He explains why Nobel prize winners from Richard Feynman to Adam Riess have all questioned the experts who came before them. Next, Brian shares the importance of the discoveries of Nobel Prize winner Sheldon Lee Glashow and why his explanation of electromagnetism is so important. Brian also explains why there is no such thing as “follow the science” and why you should be skeptical of anything where 99% of scientists are in agreement…..”

  • I am reading these stories, and just nodding my head. Still have two slide rules: My fathers pro-grade school one, and a Babcock & Wilcox circular rule. That one is kind of fun.

    Calculators are much , much better, as you can spend more time on the model than the process, but need to ‘keep it real’.

  • Because of the tiny sample so far detected
    It seems large, to me. We’ve only been looking for a few years and we’ve found that many?

    The “everything above iron is created by colliding neutron stars” theory always seemed strange to me: That’s a YUGE number of colliding neutron stars. Granted, billions of years is also a long time for them to do so, but still. Almost by definition, there must be less than half the number of neutron stars than there are supernovae and to collide they must be somewhere at least somewhat close together.

    To be sure, there is a lot more iron than gold, but in absolute terms, there’s quite a lot of gold.

    Now that I think about it, I’ve never seen numbers for amounts produced. I suppose if one collision produces gigatons of gold, perhaps we don’t need as many as I think.

    My intuition fails at these scales.

  • Typo: Less than half the number of neutron star COLLISIONS – since it takes two.

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