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Two undersea cables in Baltic Sea disrupted

(www.cnn.com)
577 points mooreds | 39 comments | 18 Nov 24 14:31 UTC | HN request time: 1.689s | source | bottom
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staplung ◴[18 Nov 24 20:22 UTC] No.42176496[source]▶
It's worth mentioning that cable breakages happen quite often; globally about 200 times per year [1] and the article itself mentions that just last year, two other cables and a gas pipeline were taken out by an anchor. The Gulf of Finland is evidently quite shallow. From what I understand, cable repair ships are likely to use ROVs for parts of repair jobs but only when the water is shallow so hopefully they can figure out whether the damage looks like sabotage before they sever the cable to repair it. Of course, if you're a bad actor and want plausible deniability, maybe you'd make it look like anchor damage or, deliberately drag an anchor right over the cables.

Cable repairs are certainly annoying and for the operator of the cable, expensive. However, they are usually repaired relatively quickly. I'd be more worried if many more cables were severed at the same time. If you're only going to break one or two a year, you might as well not bother.

1: https://www.theverge.com/c/24070570/internet-cables-undersea...

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1. ValentinA23 ◴[19 Nov 24 00:38 UTC] No.42178949[source]▶
A 1 in 36 million chance for three breaks in one day.

https://mathb.in/80217

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2. gleenn ◴[19 Nov 24 00:43 UTC] No.42178979[source]▶
That's assuming independence. I'm not ruling out sabotage but the world is often not fully independent. A storm or an anchor both may affect multiple cables if they're in generally the same area which would definitely make the probability far more likely than those stated. (edit typo)
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3. defrost ◴[19 Nov 24 00:45 UTC] No.42178990[source]▶
I'm supporting gleenn who beat me by seconds to much the same observation.

Clusters are a thing.

4. ValentinA23 ◴[19 Nov 24 01:00 UTC] No.42179089[source]▶
Indeed !

https://www.datacenterdynamics.com/en/news/lithuania-sweden-...

>Lithuania-Sweden subsea cable cut, was 10m from severed Finnish-German cable

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5. threeseed ◴[19 Nov 24 01:34 UTC] No.42179288[source]▶
And what about adding in the chances of a Russian spy ship seen relatively near by only a few days earlier:

https://www.theguardian.com/world/2024/nov/16/russian-spy-sh...

replies(1): >>42179851 #
6. CrazyCatDog ◴[19 Nov 24 03:24 UTC] No.42179837[source]▶
“Knowing that 200 undersea cables break every year globally, estimate the probability that 3 cables break in the baltic sea on the same day.”

I’m stealing this to use for grad-student mock-interviews—thank you!

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7. arandomusername ◴[19 Nov 24 03:27 UTC] No.42179851[source]▶
Irish sea is relatively near to the Baltic sea?
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8. ◴[19 Nov 24 03:42 UTC] No.42179919[source]▶
9. threeseed ◴[19 Nov 24 04:26 UTC] No.42180101{3}[source]▶
According to Google it's 854nm.

The spy ship is alleged to be able to go 15 knots which means it could make the distance in 2.5 days.

https://ukdefencejournal.org.uk/russian-spy-ship-present-off...

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10. onionisafruit ◴[19 Nov 24 05:32 UTC] No.42180330[source]▶
Today’s that day. Start the clock for the next one.
11. chgs ◴[19 Nov 24 06:10 UTC] No.42180472{4}[source]▶
Russia itself is nearer
12. kqr ◴[19 Nov 24 08:36 UTC] No.42181196[source]▶
Why is this analysis focused on the Baltics? That's p hacking, given that it happened to happen in the baltics.

Let's instead say there are roughly 20 ocean regions we would post hoc consider "the same". Now, given a breakage, what is the probability of at least two more in the same region and day? This is a Poisson distribution with lambda=200/365/20. The probability of two more independent breakages is 0.04 % for that specific day.

But again, picking a specific day would be p-hacking. Zooming out, an event that rare is expected to happen every seven years or so.

Now, "every seven years" is a far cry from "1 in 36 million." Whenever you get crazy p values like that, there is often an error or overlooked assumption in the analysis.

----

If you like this sort of thing, have a stab at forecasting competitions! I can recommend the Metaculus Quarterly Cup. The current one is in full swing so use the remaining 1.5 months of the year to practice and then you're set for when the January edition starts.

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13. Moru ◴[19 Nov 24 08:43 UTC] No.42181237[source]▶
Hint: The cables are often very close. If one breaks, the otherone also breaks :-)
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14. gitaarik ◴[19 Nov 24 09:21 UTC] No.42181451{3}[source]▶
Why would cables close to each other break?
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15. leovingi ◴[19 Nov 24 09:31 UTC] No.42181533{4}[source]▶
because if it's an accident and someone is dragging an anchor behind them, if the cables are only meters apart then they are going to cut both
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16. red_admiral ◴[19 Nov 24 09:31 UTC] No.42181536[source]▶
One a day is happenstance. Twice is coincidence. Three times is enemy action.
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17. CrazyCatDog ◴[19 Nov 24 11:50 UTC] No.42182424{3}[source]▶
Right, if it’s a case interview, then higher accuracy ought to prompt the interviewee to ask: (1) Do the 200 cuts typically occur in clusters? (2) What’s the typical density, eg are they usually collocated? (as an alternative to the above) (3) Are there pathways that avoid the sea but connect Europe and North America (getting at density in the sea in question) Etc.

That’s what makes this one so good—lots of opportunities to extend or roll-back difficulty.

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18. usrusr ◴[19 Nov 24 12:26 UTC] No.42182683{3}[source]▶
What are the chances that they break in close proximity spacially, but not temporarily? (I'm assuming that it would be headline material if the lines had disconnected within minutes)

Tangent: an attacker trying hard to provoke that kind of accident would likely not have a very fast success feedback. "Let's try once more, for good measure"

replies(1): >>42187910 #
19. froh ◴[19 Nov 24 12:48 UTC] No.42182845[source]▶
the contrast with independent random events is exactly the point of the comment you've replied to, isn't it?
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20. jeltz ◴[19 Nov 24 13:33 UTC] No.42183232{3}[source]▶
The grandparent comment is total nonsense which sounds smart but is not. Damages from accidents are not independently random either. Or do you think it is virtually impossible that 140 people die on the same airliner? It is likely the same ship cut both either by accident or intentionally.

I am leaning towards sabotage but that two cables were cut means very little.

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21. amelius ◴[19 Nov 24 13:40 UTC] No.42183294{3}[source]▶
The point is that even without a malicious actor the odds are way lower than you'd think.
22. jeltz ◴[19 Nov 24 13:42 UTC] No.42183316{5}[source]▶
No, because anchors can easily damage several cables close to each other. And that is how it almost certainly happened no matter if it was an accident or sabotage.
23. Cthulhu_ ◴[19 Nov 24 14:14 UTC] No.42183644[source]▶
A clever answer would be "it's a 50/50 chance, either it happens or it doesn't". That's statistics my simple brain can comprehend at least.
replies(1): >>42184772 #
24. sach1 ◴[19 Nov 24 14:57 UTC] No.42184096{4}[source]▶
What are the odds 140 people would all die from an airplane crash on the same day? Wild

/s

25. lrasinen ◴[19 Nov 24 15:04 UTC] No.42184163{3}[source]▶
I don't buy that number (no source is attributed to it), or rather, I don't believe there's a single incident causing this.

The C-Lion1 cable is predominantly North-East - South-West whereas the BCS cable is NW-SE. They do meet, but the C-Lion1 operator Cinia says their cable broke about 700 km from Helsinki, east of the southern tip of the Öland island. That's easily over 150 km south from where the cables meet.

Also, C-Lion1 was reported broken at 4m, and the BCS cable at 10am the previous day.

26. ValentinA23 ◴[19 Nov 24 15:17 UTC] No.42184329[source]▶
I see, this was in fact what I had in mind. The maths I posted represent the horizon of my knowledge in probability and was surprised how well o1-preview was able to output correct numerical calculations.

Having said that how would the odds look like if we factor in the fact the Baltic Sea is one of two zones with the most geopolitical tensions (along with Taiwan).

---

Thanks for the Metaculus recommendation. I was a bit disappointed in the lack of maths in the comments in general. Can you recommend something in the vein of Leetcode with various degrees of difficulty, from very basic to advanced problems ? I'm both interested in probability and statistics

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27. ◴[19 Nov 24 15:30 UTC] No.42184537[source]▶
28. ◴[19 Nov 24 15:31 UTC] No.42184557[source]▶
29. kqr ◴[19 Nov 24 15:48 UTC] No.42184772{3}[source]▶
In what way is that clever? It's clearly wrong. If it were true, we'd experience three breakages at least 150 days of the year, every year.
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30. dboreham ◴[19 Nov 24 15:50 UTC] No.42184799{4}[source]▶
FFS: NM, not nm.
31. kqr ◴[19 Nov 24 15:55 UTC] No.42184845{3}[source]▶
Something in thr vein of leetcode would be really useful to train people in forecasting, but given how subjective it is maybe difficult to pull off.
32. ValentinA23 ◴[19 Nov 24 15:59 UTC] No.42184900{4}[source]▶
I was surprised to see so many upvotes this morning and was disappointed when I realized it wasn't for another comment I made about the Anthropic Principle.

My take is that in face of coincidences supporting the emergence of intelligent life, we should expect to observe coincidences unnecessary for the emergence of life too.

An analogy: imagine you have lost the key to your mansion and try to cut one at random out of a metal sheet. If it can unlock the door, then chances are that you cut unnecessary notches (the analogy only holds for warded locks and the key you crafted is a master key).

See: https://news.ycombinator.com/item?id=42178306

I'm wondering where I'm wrong in my reasoning because the implication is weird.

33. ikiris ◴[19 Nov 24 16:38 UTC] No.42185364[source]▶
Or they’re right next to each other and the laws of physics continued to exist for the object that struck them.
34. gosub100 ◴[19 Nov 24 18:06 UTC] No.42186410[source]▶
You can't even assume they follow a normal distribution. For all we know, ships drop anchor more on certain days or weather conditions. That's just the start of the rabbit hole.
35. crote ◴[19 Nov 24 20:46 UTC] No.42187910{4}[source]▶
Still pretty decent, given the right circumstances.

For example, the 2011 earthquake in Japan resulted in damage to 7 cables[0]. But it wasn't the quake itself which instantly broke all 7 cables - they were destroyed by underwater avalanches triggered by the earthquake. Avalanches can occur hours after a seismic event, and some underwater avalanches go on for days.

I highly doubt that's the case here, but if you're asking about chances it's not as unlikely as you'd think!

[0]: https://www.theverge.com/c/24070570/internet-cables-undersea...

36. UltraSane ◴[19 Nov 24 20:50 UTC] No.42187942[source]▶
I was told in my stats class that events in the real world are almost never truly independent.
37. dgfitz ◴[19 Nov 24 21:45 UTC] No.42188435{5}[source]▶
Are they?
38. kqr ◴[20 Nov 24 12:53 UTC] No.42193511{5}[source]▶
I think it is in the spirit of Hacker News to explain rather than just whoosh someone.
replies(1): >>42193597 #
39. rrr_oh_man ◴[20 Nov 24 13:07 UTC] No.42193597{6}[source]▶
You're right, that was not kind. Apologies. It was late at night and I'd read too many depressing news (and many even more depressing, warmongering comments). Not an excuse, just a human factor.

What I should have said:

By clever GP most probably meant funny (with a hint of self-deprecation) rather than smart (or even correct).