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>"Gravity Gradiometer System Description. Gravity gradiometers are instruments and systems that detect mass density contrasts. Recent gravity gradiometer rese

>"Gravity Gradiometer System Description. Gravity gradiometers are instruments and systems that detect mass density contrasts. Recent gravity gradiometer research has focused on sea-based submarine detection applications. This concept goes several leaps forward and proposes its use in space as a passive detection system. Concept of Operations. With multiple gravity gradiometers located on multiple satellites in orbit, approaching “foreign bodies” can be passively detected. Data and measurements gathered could be combined with data from other detection devices in Kalman filtering or data fusion algorithms to enhance detection and even identification probabilities." This is interesting, the concept of a Gravity Gradiometer. I did not know that these existed, before reading this article. The following seems to be a good (albeit, somewhat commercial) page about this technology: https://www.lockheedmartin.com/en-us/products/gravity-gradiometry.html https://www.lockheedmartin.com/en-us/products/gravity-gradio... These are apparently supposed to be used in space, from a satellite, and are supposed to measure data about the earth. But, I'm wondering (from a purely theoretical basis) if a "Poor Man's Gravity Detector" could be created... Postulated theory of operation: Use two waves (they could be beams), two frequencies from the electromagnetic spectrum, and measure the time they take to cross (bounce back) from a specific distance. The idea would be that a lower frequency beam -- would be more affected by gravity than a higher one (although, perhaps this would be reversed, I don't know, experimentation is needed), and that any microscopic difference in the amount of time for the beams to be reflected might indicate the presence of higher or lower gravity. Of course, the prerequisite to creating something like this would be to have a way to test it. That is, first create a device that creates a miniscule amount of gravity (which I wouldn't know how to do -- although one guess would be that large amounts of a heavy metal would generate a microscopicly increased gravity field around it (like a milimeter away from its surface); for example, a large ball or other object made out of iron...) Anyway, an interesting article!

Doxin 6y ago
You might be interested in reading up about torsion balances, it's a scientific apparatus designed pretty much specifically to measure gravity. And indeed usually you test it (or the force of gravity itself) by using a couple globes of a large mass nearby. The device is sensitive enough to where you can't really be in the room while testing it since your gravitational field is larger than the stuff you're measuring. Of course a torsion balance really only measures the direction of the gravitational field on a single plane, not its force or total direction. https://en.wikipedia.org/wiki/Torsion_spring#Torsion_balance https://en.wikipedia.org/wiki/Torsion_spring#Torsion_balance
- peter_d_sherman 6y ago
  It's an interesting article. The gem of this article (in my opinion) is the "Animation of a torsion spring oscilating": https://upload.wikimedia.org/wikipedia/commons/transcoded/4/43/Torsion_spring_animation_fixed_camera.ogv/Torsion_spring_animation_fixed_camera.ogv.480p.vp9.webm https://upload.wikimedia.org/wikipedia/commons/transcoded/4/... Why? Well, that's one potential mechanical analogue candidate for the vibration/oscillation patterns in EM waves (although, there could be, and probably are, many others, i.e., longitudinal waves, spiral waves, etc., etc.) But that video represents one potential mechanical analogue candidate, among others... Anyway, thanks for the link!
  - Doxin 6y ago
    Nice observation. And indeed with a little work a torsion spring makes for a great analogue for waves of all sorts: https://www.youtube.com/watch?v=DovunOxlY1k https://www.youtube.com/watch?v=DovunOxlY1k
    - peter_d_sherman 6y ago
      Thank you for this link! The part starting here is particularly interesting to me: https://youtu.be/DovunOxlY1k?t=507 https://youtu.be/DovunOxlY1k?t=507 Why is that? Well, because a long time ago, I built an extremely low-power battery operated DC Tesla Coil. It worked, but the one thing I could not figure out was why the coil with the small number of turns, the coil that typically encircles the long coil with the many turns, why this coil with smaller turns -- had to be positioned a slight distance up the many turns coil, and not either directly at its end, nor at its middle. Well, this video, at the point I've noted, explains the answer why. It also explains the relationship between frequency, length of resonator, and ability to create larger amplitude waves via additive superposition, that is, the ability of one wave, travelling in one direction, has the ability to add to the amplitude/crests of another wave travelling in the other direction BUT IF AND ONLY IF THEY ARE IN PROPER ALIGNMENT! Which, incidentally, is the principle behind how a laser works (in addition to a Tesla Coil!). Also, there's the knowledge here that we can change the frequency to match the resonating coil/cavity/resonator length/etc., OR we can change the resonator length/coil length (in a Tesla Coil this is accomplished by moving the smaller outer coil with less turns on it) to match the frequency. So we can choose one to adjust to match what's needed by the other. Now, if say, a Tesla Coil is storing energy when in operation by additive/constructive interference / wavefronts adding and increasing amplitude in antinode positions, then it makes me wonder if the phenomena of electronic capacitance (i.e., a capacitor, or inversely, an inductor, which is really just another form of coil) works via waves (of some sort) adding up... Unfortunately, at this point in time, I have neither the equipment nor the knowledge nor the experience as to how to undertake such an experiment... So, I'll leave that question for scientists or future scientists -- and/or myself in the far future (disclaimer: I am not an official "scientist" <g>) -- to answer!

Doxin 6y ago

You might be interested in reading up about torsion balances, it's a scientific apparatus designed pretty much specifically to measure gravity. And indeed usually you test it (or the force of gravity itself) by using a couple globes of a large mass nearby. The device is sensitive enough to where you can't really be in the room while testing it since your gravitational field is larger than the stuff you're measuring. Of course a torsion balance really only measures the direction of the gravitational field on a single plane, not its force or total direction. https://en.wikipedia.org/wiki/Torsion_spring#Torsion_balance https://en.wikipedia.org/wiki/Torsion_spring#Torsion_balance

peter_d_sherman 6y ago
It's an interesting article. The gem of this article (in my opinion) is the "Animation of a torsion spring oscilating": https://upload.wikimedia.org/wikipedia/commons/transcoded/4/43/Torsion_spring_animation_fixed_camera.ogv/Torsion_spring_animation_fixed_camera.ogv.480p.vp9.webm https://upload.wikimedia.org/wikipedia/commons/transcoded/4/... Why? Well, that's one potential mechanical analogue candidate for the vibration/oscillation patterns in EM waves (although, there could be, and probably are, many others, i.e., longitudinal waves, spiral waves, etc., etc.) But that video represents one potential mechanical analogue candidate, among others... Anyway, thanks for the link!
- Doxin 6y ago
  Nice observation. And indeed with a little work a torsion spring makes for a great analogue for waves of all sorts: https://www.youtube.com/watch?v=DovunOxlY1k https://www.youtube.com/watch?v=DovunOxlY1k
  - peter_d_sherman 6y ago
    Thank you for this link! The part starting here is particularly interesting to me: https://youtu.be/DovunOxlY1k?t=507 https://youtu.be/DovunOxlY1k?t=507 Why is that? Well, because a long time ago, I built an extremely low-power battery operated DC Tesla Coil. It worked, but the one thing I could not figure out was why the coil with the small number of turns, the coil that typically encircles the long coil with the many turns, why this coil with smaller turns -- had to be positioned a slight distance up the many turns coil, and not either directly at its end, nor at its middle. Well, this video, at the point I've noted, explains the answer why. It also explains the relationship between frequency, length of resonator, and ability to create larger amplitude waves via additive superposition, that is, the ability of one wave, travelling in one direction, has the ability to add to the amplitude/crests of another wave travelling in the other direction BUT IF AND ONLY IF THEY ARE IN PROPER ALIGNMENT! Which, incidentally, is the principle behind how a laser works (in addition to a Tesla Coil!). Also, there's the knowledge here that we can change the frequency to match the resonating coil/cavity/resonator length/etc., OR we can change the resonator length/coil length (in a Tesla Coil this is accomplished by moving the smaller outer coil with less turns on it) to match the frequency. So we can choose one to adjust to match what's needed by the other. Now, if say, a Tesla Coil is storing energy when in operation by additive/constructive interference / wavefronts adding and increasing amplitude in antinode positions, then it makes me wonder if the phenomena of electronic capacitance (i.e., a capacitor, or inversely, an inductor, which is really just another form of coil) works via waves (of some sort) adding up... Unfortunately, at this point in time, I have neither the equipment nor the knowledge nor the experience as to how to undertake such an experiment... So, I'll leave that question for scientists or future scientists -- and/or myself in the far future (disclaimer: I am not an official "scientist" <g>) -- to answer!