4 ms·
"Vast" really shouldn't have been eliminated from the title, because interferometers have been measuring distances with nanometer precision since even before th
by kragen 2y ago
"Vast" really shouldn't have been eliminated from the title, because interferometers have been measuring distances with nanometer precision since even before there were lasers, and lasers have been used in interferometers since the first laser in 01960. Victorian-era interferometers, commonly used for grinding telescope mirrors, could only measure distances of a few meters with precision in the hundreds of nanometers.
However, laser interferometers were already quite good; LIGO, most famously, detected gravitational waves by measuring strains of around 10⁻²⁰ over a distance of 1120 km, which works out to a change in distance of less than 0.000012 nanometers, much less than the width of a proton.
The news here actually seems to be that "A new way to gauge distance using lasers can measure lengths of more than 100 kilometres ... To continue reading, subscribe today with our January sale." So, uh, I don't know, maybe the reporter wasn't familiar with LIGO and thought that nanometer-precision interferometry over kilometers was new? Sitkack, you say there's a paper somewhere?
- stavros 2y agoOooh it's the guy with octal years!
- greenbit 2y agoNoticed that too, but it has a '9' in it. Best guess is, he's not about to let the Y10K problem catch him napping.
- __MatrixMan__ 2y agoIt's kind of silly, but I do like the philosophy behind it: https://longnow.org/ideas/long-now-years-five-digit-dates-and-10k-compliance-at-home/ https://longnow.org/ideas/long-now-years-five-digit-dates-an...
- cryptonector 2y agoSee The Long Now Foundation.
- dmd 2y agoWhy not two zeros? Or three, or more?
- __MatrixMan__ 2y agoIf the people around you are planning for 1y and you're suggesting they plan for 7976y, I think that's probably radical enough. To suggest they plan for 97975y or 997975y seems a bit obnoxious. At that point you're either just being contentious for the sake of it, or you're pretentiously implying that you have godlike predictive power.
- kragen 2y agoI wholeheartedly support your decision to use three or more zeros on your years in the future.
- opwieurposiu 2y agoLIGO can accurately measure small (1/2 wavelength) changes in distance, but it does not measure absolute distance. Absolute is a lot harder to do with interferometers vs. relative measurements.
- kragen 2y agoAha! Yes, very much harder.
- sitkack 2y agoI skipped the article, went directly to the paper https://arxiv.org/abs/2412.05542 https://arxiv.org/abs/2412.05542 It is very readable. This measures absolute distance. LIGO was its own thing https://en.wikipedia.org/wiki/LIGO https://en.wikipedia.org/wiki/LIGO many people, big vacuum. Two sites, one by Hanford the other in a swamp https://www.ligo.caltech.edu/WA https://www.ligo.caltech.edu/WA https://www.ligo.caltech.edu/LA https://www.ligo.caltech.edu/LA
- kragen 2y agoThank you! I'll check it out.