7 ms·

What could we do with more accurate atomic clocks that we cannot do with current ones?

defrost 2y ago
For interest, Precision Vs Accuracy, Atomic Clocks Vs Sapphire Oscillator https://news.ycombinator.com/item?id=28232645 https://news.ycombinator.com/item?id=28232645 Detecting gravity waves with large laser triangles required a few advances in technology - precision clocks was one. Not so long ago had you asked your question the answer would have been "detect gravity waves".
fanf2 2y ago
Most units of measurement are derived from the second, so the more precise our frequency standards, the more precise everything else can be. Things like interferometry and spectroscopy depend directly on very precise frequency standards.
btilly 2y ago
The article points to a use I wouldn't have thought of. The deeper you go into a gravitational field, the slower time goes. Therefore comparing clocks in different places gives a way to measure gravity. These clocks could be sufficiently precise to find mineral deposits underground from their gravity signature.
- defrost 2y ago
  > These clocks could be sufficiently precise to find mineral deposits underground from their gravity signature. We've been doing that since the 1960s at least with such things as the LaCoste & Romberg gravimeter (1936). You can download, see online the "Geoid" https://americanhistory.si.edu/collections/nmah_865074 https://americanhistory.si.edu/collections/nmah_865074 https://en.wikipedia.org/wiki/Gravimetry https://en.wikipedia.org/wiki/Gravimetry https://en.wikipedia.org/wiki/Geoid https://en.wikipedia.org/wiki/Geoid Magnetic anomalies also highlight inteesting places for minerals, the issue with both magnetic and gravity fields variations lies with determining the "true" depth to target (medium sized shallow target, or massive deep taget?) which is known as an inversion problem.
  - btilly 2y ago
    Yes, but a better clock means more precise measurements, means we can locate smaller masses to higher precision.
    - defrost 2y ago
      Does it? Inversion is rarely unique, and it's not due to the precision with which the field is measured. https://earthsciences.anu.edu.au/study/student-projects/novel-approaches-geophysical-inversion https://earthsciences.anu.edu.au/study/student-projects/nove... https://inside.mines.edu/~rsnieder/snieder_trampert_00.pdf https://inside.mines.edu/~rsnieder/snieder_trampert_00.pdf Epilogue: Linear inverse problem theory is an extremely powerful tool for solving inverse problems. Much of the information that we currently have on the Earth’s interior is based on linear inverse problems Despite the success of linear inverse theory, one should be aware that for many practical problems our ability to solve inverse problems is largely confined to the estimation problem.
      - btilly 2y ago
        Yes, inverse problems are hard. And not always possible in practice. See, for example, https://www.ams.org/publicoutreach/feature-column/fcarc-199706 https://www.ams.org/publicoutreach/feature-column/fcarc-1997... for a case where one isn't possible. That said, the gravity technique is one that actually gets used today. With better precision, it can be even more useful than it already is.
    - JanisErdmanis 2y ago
      The problem is that the planet could be hollow and produce the same gravitational measurements on the surface and outside. It needs to be coupled with a model that introduces constraints for the inverse problem to be defined.
      - blincoln 2y ago
        Since mining is only concerned with material that's within maybe 0.1% of the distance from the surface to the core, seems like you'd just need to move the sensor around and make sure the signal changes about where you'd expect for a mass of X Kg at a depth of Y meters instead of a supermassive chunk of dense material much deeper. Or, to put it another way, build a grid map of the area and subtract any background signal. Would that not work for some reason?

For interest, Precision Vs Accuracy, Atomic Clocks Vs Sapphire Oscillator https://news.ycombinator.com/item?id=28232645 https://news.ycombinator.com/item?id=28232645 Detecting gravity waves with large laser triangles required a few advances in technology - precision clocks was one. Not so long ago had you asked your question the answer would have been "detect gravity waves".

fanf2 2y ago

Most units of measurement are derived from the second, so the more precise our frequency standards, the more precise everything else can be. Things like interferometry and spectroscopy depend directly on very precise frequency standards.

btilly 2y ago

The article points to a use I wouldn't have thought of. The deeper you go into a gravitational field, the slower time goes. Therefore comparing clocks in different places gives a way to measure gravity. These clocks could be sufficiently precise to find mineral deposits underground from their gravity signature.

defrost 2y ago
> These clocks could be sufficiently precise to find mineral deposits underground from their gravity signature. We've been doing that since the 1960s at least with such things as the LaCoste & Romberg gravimeter (1936). You can download, see online the "Geoid" https://americanhistory.si.edu/collections/nmah_865074 https://americanhistory.si.edu/collections/nmah_865074 https://en.wikipedia.org/wiki/Gravimetry https://en.wikipedia.org/wiki/Gravimetry https://en.wikipedia.org/wiki/Geoid https://en.wikipedia.org/wiki/Geoid Magnetic anomalies also highlight inteesting places for minerals, the issue with both magnetic and gravity fields variations lies with determining the "true" depth to target (medium sized shallow target, or massive deep taget?) which is known as an inversion problem.
- btilly 2y ago
  Yes, but a better clock means more precise measurements, means we can locate smaller masses to higher precision.
  - defrost 2y ago
    Does it? Inversion is rarely unique, and it's not due to the precision with which the field is measured. https://earthsciences.anu.edu.au/study/student-projects/novel-approaches-geophysical-inversion https://earthsciences.anu.edu.au/study/student-projects/nove... https://inside.mines.edu/~rsnieder/snieder_trampert_00.pdf https://inside.mines.edu/~rsnieder/snieder_trampert_00.pdf Epilogue: Linear inverse problem theory is an extremely powerful tool for solving inverse problems. Much of the information that we currently have on the Earth’s interior is based on linear inverse problems Despite the success of linear inverse theory, one should be aware that for many practical problems our ability to solve inverse problems is largely confined to the estimation problem.
    - btilly 2y ago
      Yes, inverse problems are hard. And not always possible in practice. See, for example, https://www.ams.org/publicoutreach/feature-column/fcarc-199706 https://www.ams.org/publicoutreach/feature-column/fcarc-1997... for a case where one isn't possible. That said, the gravity technique is one that actually gets used today. With better precision, it can be even more useful than it already is.
  - JanisErdmanis 2y ago
    The problem is that the planet could be hollow and produce the same gravitational measurements on the surface and outside. It needs to be coupled with a model that introduces constraints for the inverse problem to be defined.
    - blincoln 2y ago
      Since mining is only concerned with material that's within maybe 0.1% of the distance from the surface to the core, seems like you'd just need to move the sensor around and make sure the signal changes about where you'd expect for a mass of X Kg at a depth of Y meters instead of a supermassive chunk of dense material much deeper. Or, to put it another way, build a grid map of the area and subtract any background signal. Would that not work for some reason?