I think there is a real chance this is a smokescreen or diversion, but if it is real, then I'm actually kind of shocked that it could ever work. I guess once in a while tech surprises me. I mean, that weak a signal + the inverse square law + everything in the area (living things, static electricity, aircraft systems, geomagnetic)
I mean... wow. That really works? Damn.
It really makes me think that if it's possible to pick up a magnetic signal that weak, what else could be inferred from a signal that weak? Mineral deposits? ship wrecks? Hidden tunnels?
Murmur BS aside - holy shit, they had to abandon two C-130 class planes because they got stuck in the mud? And lost an A-10 Warthog on top of the original F-15?
"Many people said Jimmy Carter knew how to fuck up in Iran, but those people never met me because I am the world's greatest expert in fucking up in Iran, and there will be so much fucking up you'll get sick of me fucking up."
Just a few numbers and even one equation, sorry:
The heart is a magnetic dipole, and the field of a magnetic dipole decays as 1/r³. Therefore, if it can be detected at a distance of 5 cm, then at a distance of 50 kilometers it will be (5,000,000 cm / 5 cm)³ = 10¹⁸ times weaker.
A quintillion times smaller. I think the discussion of signal-to-noise ratio is a bit... uh... misleading.
I don't think it's too misleading. There have been atomic-optical magnetometers developed with sensitivity of 10s of fT/√Hz, so approaching the quantum noise limit. The issue seems to be SNR to a certain extent.
In an ideal situation, such as being isolated in a desert, detecting the heart within meters is achievable, within a kilometer plausible, within 10s of kilometers implausible.
It's also a matter of just getting plausible detection. If you get a reading that might be a heart, you can move closer. Being able to move the detector provides much better search capabilities.
The consensus here seems to be it's unlikely to be feasible. Further if it was true why would they reveal it and remove any advantage of it secrecy?
So the question is why make up such a story? Why reveal it through Trump? What else about the story is false? Was this all cover to go into that nuclear facility?
Would they really need all of this equipment and troops to go get one guy? Isn't it usually a couple helos, some tankers, and some air cover?
More than likely this is a cover story for the RQ-180 orbiting
At high altitude and using its thermal IR cameras for real time imaging.
Remember Trump said something about seeing the pilot move especially
His head.
It seems that the majority of the skepticism comes from the classical understanding of magnetism and magnetic fields.
It seems incredulous that you can detect the magnetic dipole of a heartbeat at distance because the magnetic field generated by a heart is essentially nonexistent. However, there /is/ a measurable effect from the magnetic vector potential even if the magnetic field is or is essentially 0. This seems counterintuitive, but has been experimentally verified [0, 1].
There are a myriad of quantum magnetometers with the main categories of superconducting (SQUID), atomic, and nitrogen-vacancy (NV) [2]. Superconducting magnetometers require cryogenics, so we can immediately discount its usage. Nitrogen-vacancy magnetometers can detect high frequency magnetic fields, which a heartbeat is not, and are less sensitive than atomic magnetometers. Therefore, NV magnetometers can be disregarded.
Now, for atomic magnetometers. Optically pumped atomic magnetometers (OPAM). These are highly portable and extremely sensitive (fT/√Hz), with some OPAMs approaching the quantum noise limit [3]. Moreover, the detection of a magnetic vector potential is possible [4].
Another type of atomic magnetometer is the Spin Exchange Relaxation Free (SERF) magnetometer. SERFs are even more sensitive than standard OPAMs (aT/√Hz). So, likely, some form of atomic magnetometer is being used.
Nonetheless, they most likely used a mixture of other methods to reduce the search area.
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[ 3.1 ms ] story [ 37.1 ms ] threadOr an excellent fictional coverup for a failed Isfahan raid, not that such a thing would ever be considered by rational officers.
I mean... wow. That really works? Damn.
It really makes me think that if it's possible to pick up a magnetic signal that weak, what else could be inferred from a signal that weak? Mineral deposits? ship wrecks? Hidden tunnels?
This looks like a massive fuckup!
In an ideal situation, such as being isolated in a desert, detecting the heart within meters is achievable, within a kilometer plausible, within 10s of kilometers implausible.
It's also a matter of just getting plausible detection. If you get a reading that might be a heart, you can move closer. Being able to move the detector provides much better search capabilities.
So the question is why make up such a story? Why reveal it through Trump? What else about the story is false? Was this all cover to go into that nuclear facility?
Would they really need all of this equipment and troops to go get one guy? Isn't it usually a couple helos, some tankers, and some air cover?
It seems incredulous that you can detect the magnetic dipole of a heartbeat at distance because the magnetic field generated by a heart is essentially nonexistent. However, there /is/ a measurable effect from the magnetic vector potential even if the magnetic field is or is essentially 0. This seems counterintuitive, but has been experimentally verified [0, 1].
There are a myriad of quantum magnetometers with the main categories of superconducting (SQUID), atomic, and nitrogen-vacancy (NV) [2]. Superconducting magnetometers require cryogenics, so we can immediately discount its usage. Nitrogen-vacancy magnetometers can detect high frequency magnetic fields, which a heartbeat is not, and are less sensitive than atomic magnetometers. Therefore, NV magnetometers can be disregarded.
Now, for atomic magnetometers. Optically pumped atomic magnetometers (OPAM). These are highly portable and extremely sensitive (fT/√Hz), with some OPAMs approaching the quantum noise limit [3]. Moreover, the detection of a magnetic vector potential is possible [4].
Another type of atomic magnetometer is the Spin Exchange Relaxation Free (SERF) magnetometer. SERFs are even more sensitive than standard OPAMs (aT/√Hz). So, likely, some form of atomic magnetometer is being used.
Nonetheless, they most likely used a mixture of other methods to reduce the search area.
[0] https://www.feynmanlectures.caltech.edu/II_15.html#Ch15-S5
[1] https://www.youtube.com/watch?v=XKSjCOKDtpk
[2] https://www.nist.gov/quantum-information-science/sensors-mag...
[3] https://pubs.aip.org/aip/apl/article-abstract/89/21/214106/3...
[4] https://pubs.aip.org/aip/adv/article/13/2/025127/2877320/Dif...