Apple spends boatloads and boatloads of more money than Tesla can economically afford on research, development, and buyouts; I guess. Why isn't Apple announcing 0.00001 percent the magical things Elon Musk is?
Lot of dismissive reactions to these questions, but there actually are non sound related signals we use to detect submarines and there is absolutely research on how to do that from space.
This article is great, but just read the "Signal Processing" section if you're interested in space.
https://www.aspistrategist.org.au/prospects-for-game-changer...
Interesting article. Also, we are now able to reconstruct a conversation by analyzing the movement of the glass on a window to the room where people are talking. It doesn't seem absolutely out of reach that we could some day detect huge underwater vessels from analyzing surface perturbations.
"reconstruct conversation glass vibration" brings up a lot of relevant results from a 2014 story from MIT. Sounds like it works in principle with any medium that can have its visible vibrations monitored (bag of chips is the main example, but they talk about other options such as plants or a glass of water).
Not sure if they are, but I do know that the US Navy funded a lot of oceanographic research into predicting and understanding bioluminescence of marine organisms for this very reason. The surface waters of the North Atlantic have massive spring blooms of phytoplankton, which are sometimes bioluminescent, and could certainly give away the presence of a large subsurface vessel, possibly from space.
next time you're out on the open ocean check how far down into the water you can see, and then check out this graph [0] of electromagnetic radiation absorption of water: visible light is the best case scenario.
there's a reason sonar is acoustic and not light based
This is fairly open secrets to the degree that it is secret at all so it probably also is no big secret that passive and active countermeasures are used to prevent these techniques.
The US Navy has researched the possibility of detecting shallow submarines from space since at least the 1990s by looking for subtle wake turbulence on the surface. The results are classified so we don't know if they were ever successful. It's not completely impossible, but the signal to noise ratio would be extremely low.
Any detection from space would have to use an optics system to detect light bouncing off the submarine. This light could be either the naturally occurring visible light, or some form of active system (probably emitting radar waves).
Unfortunately light can't penetrate very far into water, so this idea is a non-starter. Light can barely make it 200m into the ocean (meaning 100m depth for light to make a round-trip and back for detection), and subs can go as deep as 300m.
Any satellite-based detection system would have to rely on catching the sub while on the surface. I'm positive this is being attempted constantly, but catching a sub at depth is an entirely different manner.
Using what technology? I can imagine in some future there being the means, but I find it hard to believe we have that level of tech available to the sort of packages we can aloft into orbit now.
Subs would be detectable using magnetometers, except that they have electromagnets in them to hide their magnetometer footprint. Still, this is not perfect.
Large subs have somewhat detectable gravitometric footprints that could be observed from space, indeed.
These subs are large, metallic, full of electric equipment, and heavy. They have magnetic and gravitational effects on their surroundings. They also have electromagnets to help hide their magnetic signatures. A network of very sensitive satelites with very precise clocks could be used to detect gravitational anomalies -- maybe, I'm not sure what kind of precision would be needed, or if that is achievable.
Closed cycle steam generation plants aren't going to exhaust much. They can't filter seawater fast enough for use and you couldn't run seawater through those systems w/o messing them up.
Subs must necessarily produce heat. That heat has to go into the surrounding (usually very cold) water. This is unavoidable. Those nuclear reactors are cooled with that surrounding water, though obviously through heat exchangers.
Let me get this straight - there's a technique for detecting changes in the surface temperature of the water from a submarine that's probably hundreds of meters below the surface?
