this post was submitted on 26 Dec 2024
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NATO is ready to help Finland and Estonia as Finnish authorities probe an oil tanker that sailed from a Russian port over the possible "sabotage" of a power cable linking the two member countries, alliance chief Mark Rutte has said.

"Spoke with (Estonian Prime Minister) Kristen Michal about reported possible sabotage of Baltic Sea cables. NATO stands in solidarity with Allies and condemns any attacks on critical infrastructure.

"We are following investigations by Estonia and Finland, and we stand ready to provide further support," Mr Rutte said on X.

Earlier, Finnish authorities said they were investigating an oil tanker that sailed from a Russian port for the "sabotage" of a power cable linking Finland and Estonia that was damaged the previous day.

The Cook Islands-registered ship, named by authorities as the Eagle S, was boarded by a Finnish coast guard crew which took command in the Baltic Sea and sailed the vessel to Finnish waters, a coast guard official told a press conference.

"From our side we are investigating grave sabotage," Robin Lardot, Director of the Finnish National Bureau of Investigation, said.

"According to our understanding an anchor of the vessel that is under investigation has caused the damage," he added.

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[โ€“] [email protected] 1 points 19 hours ago (8 children)

Can we develop a laser that we mount on a tower in each country that just transmits those same information, instead of going through a cable in international waters?

I mean how big could the cables be? Just add more lasers for more information. Like, just mount 1000 lasers on one end pointed at 1000 receivers on the other side, do the same for the other way around. Boom, no more cable cutting. Unlike radio, you don't run out of the spectrum. Need more bandwidth? Just ADD MORE LASERS!!!

Why don't countries just do this?

(Is my idea stupid? ๐Ÿค”)

[โ€“] [email protected] 2 points 5 hours ago* (last edited 5 hours ago)

Atmosphere and could still be disturbed or intercepted with an airplane.

[โ€“] [email protected] 1 points 4 hours ago

Point to point communication is already pretty well served by microwave links, no?

[โ€“] [email protected] 8 points 13 hours ago (1 children)

I just learned about this: https://en.m.wikipedia.org/wiki/Optical_telegraph

Your idea worked for a long time and in France where they had a well established system it took awhile for electric telegraph to win over it.

Many of the problems they had lasers would also face, including atmosphere, and I'm curious if people could intercept the signal without being detected, which was certainly a big issue for them.

[โ€“] [email protected] 5 points 13 hours ago (1 children)

Iโ€™m curious if people could intercept the signal without being detected, which was certainly a big issue for them.

I mean, just encrypt it.

Radios can be intercepted too, and thats why they are encrypted, just do the same with the lasers: encrypt the data before encoding to the laser signals.

[โ€“] [email protected] 2 points 13 hours ago* (last edited 13 hours ago)

Great point. We have some new tools since the original optical telegraph.

The original did have error correction codes to prevent man-in-the-middle attacks but the wiki page has a story about how that was defeated

[โ€“] [email protected] 28 points 19 hours ago (3 children)
[โ€“] [email protected] 19 points 18 hours ago (1 children)

Just use heavier light so it curves with the earth. Duhhh ;)

[โ€“] [email protected] 7 points 18 hours ago (2 children)

You have to be careful with that kind of thing, because too much heavy light will make a light black hole.

[โ€“] [email protected] 5 points 17 hours ago

I believe that's how black light gets made.

[โ€“] [email protected] 2 points 16 hours ago

not a grey hole!!

[โ€“] [email protected] 8 points 18 hours ago* (last edited 18 hours ago) (3 children)

Lol I forgor ๐Ÿ’€

But I used this calculator and it says if we have building as tall as the Empire State Building (380 meters tall), we can shine the laser towards another building of the same height thats 130 km away, it would still be above the curvature, along with the top 100 meters (approximately) of the building.

See the calculations:

So we just need relays towers every 130 kilometers or so.

๐Ÿค“

(Sorry I got a bit goofy, bit its technically possible, no? It would be the most ridiculous information transfer system ever, but I bet the tourist attraction would bring in a lot of money. Big Lasers = Very Cool ๐Ÿ˜Ž)

[โ€“] [email protected] 7 points 17 hours ago (1 children)

At this point you just put satellites in orbit to bounce the laser / maser off of, then you dont need to build big towers. Either way your communications beam will be affected by weather conditions (mostly humidity).

The sattelite beam would probably perform better in general. It has a longer path, but less of the transmission path is through the dense part of the atmosphere.

[โ€“] [email protected] 8 points 17 hours ago

geosynchonous orbit is very high latency and thus not accaptable for most communication. Low earth is okay but now you need a lot of sattelites just so one is in view.

[โ€“] [email protected] 4 points 17 hours ago (1 children)

Has to be an extra 70+ meters higher than that because as your math shows, the straight line will intersect the curvature of the earth meaning any container ship passing would block the signal.

[โ€“] [email protected] 3 points 17 hours ago* (last edited 17 hours ago) (1 children)

Huh?

It shows that if h0 is 380 meters then a building 130 km away would be below the curvature if its less than 286.44 meters tall, thus not visible, but any portion of a building taller than that would be visible.

So two 380 meter buildings 130 km away is visible to each other (at least the portion above 286.44 meters).

The 69 kilometers is the distance to horizon... nothing to do with the buildings heights...

Am I not understanding this correctly?

Edit: about this:

any container ship passing would block the signal.

Yea the top of the building would be above the horizon by almost 100 meters, definitely visible

[โ€“] [email protected] 3 points 16 hours ago (1 children)

What is the height of the laser beam above the horizon at distance d1?

The picture and the calculator implies it is 0.

Now imagine something with non zero height is sitting at the curvature midpoint at distance d1. Container ships are 70+ meters high.

[โ€“] [email protected] 3 points 16 hours ago

If one building is 380 meter, but the other one at 130 km away is 286.4434 meters tall, yes it would be zero. But my (hypothetical) proposal would say both buildings are 380 meters, so there would be a 93 meter clearance for ships to pass below without interrupting the lasers.

[โ€“] [email protected] 3 points 18 hours ago

Nuh-uh!

It's flat and we're on a giant turtle. I'm for the lasers.

[โ€“] [email protected] 16 points 18 hours ago

In addition to the curvature of the Earth as mentioned by @[email protected], there is also atmospheric dispersion (implied by @[email protected] answer) and... geological movement.

Land moves slowly due to geological faults, thermal expansion, the gravitational influence of the Moon, ground vibrations (such as those caused by cars and trucks rolling over the ground), among other reasons. This is not a short-term problem for fiber optic cables (because fiber optic cables have some extra length to compensate if the distance becomes slightly longer or shorter), but it is a problem for lasers, because they need to be precisely aimed at a receiver area.

Just micrometers (less than 1 mm) of displacement are enough to mess with the phase of the light. In fact, this is a well-known phenomenon and has been well-exploited in optical interferometry experiments (such as LIGO, which observes small fluctuations in alignment to detect gravitational waves).

Air movement (wind and convection currents) also provokes slight light displacement, enough for laser misalignment.

[โ€“] [email protected] 10 points 18 hours ago (1 children)

Fibre optic glass is much more transparent than air, as I understand it. A laser can have much lower power and reach farther through a cable. The cable 'bounces' the signal through optical refraction, so it doesn't need to be aimed precisely.

[โ€“] [email protected] 8 points 18 hours ago (1 children)

Also, air is turbulent. Glass and plastic are not.

Laser communication between space and ground is achievable, but only because there's so much less atmosphere in between.

Granted, advancements in laser communication may make free space optics more effective in the future, but it's not effective right now.

[โ€“] [email protected] 3 points 13 hours ago

I want artistically turbulent glass now, dangit

[โ€“] [email protected] 7 points 18 hours ago

Well, this was a power cable this time, not a communication cable.

As for your idea, atmospheric distortion makes lasers not viable beyond a certain distance. Even on a crystal clear day the light would be too distorted/spread out to be useful beyond a few miles. The cables use fiber optic, which mitigates the distortion problem, but still requires repeaters to boost the signal every 100 kilometers or so.

[โ€“] [email protected] 6 points 19 hours ago (1 children)

Stupid: somewhat (isn't this just direct satellite communications?)

applicable: absolutely not since Estlink is not about communication but power transfer,

Hilarious: yup

[โ€“] [email protected] 2 points 18 hours ago (2 children)

Hmm, can some scientist please invent an energy transfer system capable of transfering electricity via lasers? Please?

Strap Darth Sidious on top of a tower if you have to. It'd be epic!

[โ€“] [email protected] 4 points 18 hours ago

See also "death ray"

[โ€“] [email protected] 2 points 17 hours ago

See "power beaming"