yesterday at 5:40 PM
I work on autonomous submarines that image the seafloor, and let me tell you it is very hard to engineer deep ocean systems. Just operationally, testing things in rolling waves is a brutal job. Arguably at parity with space as an engineering design environment.
yesterday at 6:38 PM
I (briefly) worked as a test engineer on a similar kind of contract. To meet the UX requirements for the system we were building, it had to be reliably operable in sea state 7+. The customer wanted touch screen interfaces. I exited that project when they were looking for volunteers to go spend time offshore in the Gulf of Alaska in bad weather, because that was the test environment they could find that met the requirements. Insanity.
yesterday at 6:52 PM
Shoulda told them to test it on roller coaster with a splash zone. Way easier to get engineers to come to work at Six Flags than brave the briny deep.
yesterday at 6:17 PM
I forget who said it, but there's a quote about how _of course_ we know more about space than the bottom of the ocean - in space we only have to deal with one atmosphere.
yesterday at 7:10 PM
>only have to deal with one atmosphere.
A difference of one atmosphere?
yesterday at 7:55 PM
There’s only one atmosphere of pressure from inside to outside. Under the sea the direction is reversed and pressure is much higher.
yesterday at 8:05 PM
The one atmosphere that telescopes are looking through. It is nowhere near as problematic as looking through seawater.
yesterday at 8:14 PM
But space telescopes exist where you don't have to deal with one atmosphere.
today at 12:20 AM
I found that sea, space and automotive are the three most hostile environments, each with very different requirements that made it hard in different ways.
yesterday at 4:53 PM
I worked for an L1 blockchain for a couple years and while the term "decentralized" is bandied about a bit too much, reading articles like this does underscore how vulnerable global traffic is.
e.g. some EVM chains have a majority of "stake" in either one country or several adjacent countries (particularly in Asia). A cable cut there, which the article points out has happened, can lead to the blockchain getting cut off or even halting.
yesterday at 5:09 PM
I think people conflate decentralization with redundancy or resilience. IMO it just means you have multiple points of failure instead of one.
yesterday at 7:18 PM
10 years ago the talk of hackers partitioning the internet to double spend BTC all seemed a bit far fetched. But now crypto has trillions in market cap and governments involved -- governments that sometimes cut network cables just to send a message. The "means" and "motive" exploded by 100x, did anyone find a way to close the "opportunity" or did people just stop talking about it lol?
today at 12:27 AM
You'd also need to take down fleets of satellites in space. Double-spends aren't really easy to profit from either.
today at 12:25 AM
Not sure about other blockchains but with Bitcoin, you only need one node to connect via satellite and the chain is good. In fact, there are satellites that broadcast blocks from space (no ISP required). [0]
[0] https://blockstream.com/satellite/
yesterday at 4:58 PM
I think the issue is that centralization is more economical due to scale, but that assumes all else (geopolitics or other black swan events) don't impact things.
We saw a similar thing with supply chains and chip suppliers.
yesterday at 5:42 PM
> reading articles like this does underscore how vulnerable global traffic is.
Then also remember that the internet haven't seen a global outage since forever, worst parts have been when some submarine cables break and traffic has to route around it, but never has the entire thing fully went down. Considering how most of it is built with bandaids, silver-tape and WD40, it's surprising it is as resilient as it is.
yesterday at 6:43 PM
If you care at all about this, you'll love Neal Stephenson's long article Mother Earth, Motherboard: https://www.wired.com/1996/12/ffglass/
yesterday at 11:14 PM
Scan from the print issue: https://archive.org/details/wired-magazine-04.12-1996-decemb...
yesterday at 8:06 PM
I used to have a print copy of that issue. That single article was something like 50-60 pages long with all the (fabulous and informative) pictures.
yesterday at 10:55 PM
I think about this often.
yesterday at 6:15 PM
Ah, the “unusually unlucky” cables serving Taiwan and in the Baltics.
Like statistically impossibly unlucky.
today at 2:25 AM
Yes, I admire the restraint required to not put "unlucky" in quotes.
yesterday at 8:29 PM
At least for the Baltics, there is the unique aspect of the infamous "shadow fleet". Utterly derelict ships with barely qualified crews.
today at 1:01 AM
Ordered to swim back and forth with anchor down until they catch something.
yesterday at 5:49 PM
I have been trying, and failing, to buy a cross section of a submarine cable. I'd love one as an art piece for my house.
yesterday at 7:01 PM
Everyone in the industry I can find including people who do recycling of submarine cables. It seems that cross sections are sometimes given away as gifts as part of a project but are really hard to find.
yesterday at 5:51 PM
who have you asked?
yesterday at 6:23 PM
yesterday at 10:13 PM
I recently learnt about Transatlantic telegraph cable: https://en.wikipedia.org/wiki/Transatlantic_telegraph_cable
It was laid in 1858. During its brief three-week lifespan, only 732 messages (amounting to roughly 400 total telegrams) were successfully transmitted before the cable died.
today at 12:58 AM
The Digital Antiquarian made fantastic "A Web Around the World" series of articles covering start of telegraph all the way to first Web Browser in a style of James Burke Connections.
A Web Around the World, Part 1: Signals Down a Wire January 7, 2022 https://www.filfre.net/2022/01/a-web-around-the-world-part-1...
https://www.filfre.net/2022/01/a-web-around-the-world-part-2...
https://www.filfre.net/2022/02/a-web-around-the-world-part-3...
First working cable was sort of Monty Python Swamp Castle deal.
yesterday at 10:45 PM
Likely failure was due to not being insulated properly and Wildman Whitehouse:
https://en.wikipedia.org/wiki/Wildman_Whitehouse
yesterday at 8:49 PM
I found https://smc.peering.tw/ fascinating. It shows an up to date status of submarine links to Taiwan and you can see many of them are having outages. Even more interesting is the historical view showing that the system operates in an always partly degraded regime
yesterday at 7:14 PM
My son's school computing teacher was convinced that these oceanic communication cables float on the surface - to the extent they had a bit argument about it in class. I'm not sure how the teacher thought ships navigated around them.
yesterday at 5:55 PM
Underwater cables have been one of the more awe inspiring things for me. I know nothing about them but they seem SO crazy and yet we have them running all across the oceans. .·°՞( ̑ ᗜ ̑ )՞°·.
yesterday at 11:12 PM
This was a fascinating, well written article.
yesterday at 6:25 PM
How practical would be a mesh of satellites shooting lasers at each other, compared to undersea fiber-optic cables?
Alternatively, is there a wavelength of light to which water is completely transparent? Can we shoot lasers of that frequency through open water instead of through cables?
Maybe something that could be mounted on blue whales?
yesterday at 7:28 PM
Starshield (military arm of SpaceX/Starlink) does this for satellite imaging.
Normally in imaging, you first need to get the satellite over the location you want to image, at the right time - then let it orbit over a downlink location.
There are companies making a lot of money by having downlink capability in useful places (eg: near the poles) - combined with a fat pipe to the Internet.
With Starshield, the satellites talk to each other over laser - so the satellite doesn't have to wait to travel to a downlink location - just relay to of that is already there.
So for certain special cases it can help - but I think you'll find a cable stuffed with multimodal fiber had vastly more bandwidth.
yesterday at 8:29 PM
Depends on a lot of things, but most undersea cables have several fibers (typically around 10 fibers), and each fiber runs many wavelengths (typically 40 or 80). Whatever your bandwidth is per wavelength (there are lots of options, at different costs, up to maybe 400gbps) that's a huge amount of bandwidth to replace.
Space lasers probably don't do multiple wavelengths, and aiming a lot of laser transceivers is going to be challenging.
> Alternatively, is there a wavelength of light to which water is completely transparent? Can we shoot lasers of that frequency through open water instead of through cables?
Even if you could, that's only going to work for short hops, long distance fiber includes repeaters every so often (50-100 km) to deal with loss, it would be tricky to build those under the sea ... and you need to power them, which means a cable, might as well include fiber with your power cable.
yesterday at 6:34 PM
Someone else with more experience could chime in but I would put it at less practical due to latency (sats are very high up), bandwidth (one laser vs a bundle of 1000s of fiber optic cables), cost (to overcome latency you need a closer orbit which requires more sats), single point of failure, lifespan, intercepted communications, solar flares… and that’s just off the top of my head.
yesterday at 6:41 PM
I don't actually think latency would be that much worse.
Of course, it depends on the altitude of the satellite but speed of light in a fiber optic is only ~2/3rds of speed of light in a vacuum so you can afford some detour
yesterday at 9:03 PM
You probably can’t get under 500 km orbit, so 2000 km round trip is the shortest you can do between you and a ground based server. That’s 150 ms minimum round trip latency.
yesterday at 6:52 PM
> speed of light in a fiber optic is only ~2/3rds of speed of light in a vacuum
That made me wonder: Why can't we use vacuum cables?
(the sort of questions I should probably be bothering an LLM with.. someone should make a LMGPTTFY)
yesterday at 7:38 PM
If you figure out how to make cheap vacuum cables you will probably become very rich.
But otherwise chains of microwave links does get much closer to c in applications where you want absolute lowest latency (or much more commonly, when digging a fiber line is too expensive)
yesterday at 10:11 PM
Not vacuum but an inert gas: https://www.thefoa.org/tech/ref/fiber/Hollow-core-fiber.html
yesterday at 7:34 PM
> Why can't we use vacuum cables?
Hollow-core fiber is basically this!
> LMGPTTFY
"let me go prompt that for you" or "let me GPT that for you"?
today at 1:47 AM
> "let me go prompt that for you" or "let me GPT that for you"?
yes
yesterday at 8:01 PM
latency lower for satellites, trading firms have looked at this already, no idea if anyone has actually done it
bandwidth would indeed be worse
yesterday at 6:50 PM
starlink sats are some of the lowest orbiting satellites in space - 330-370km for v3. this helps latency as well as easy deorbit at end of life. the v3 sats have multiple 400 gbps lasers for meshing... I can't decide if your comment is sarcasm or not actually because starlink is fully functional and doesn't have any of those issues
yesterday at 6:38 PM
A submarine cable is a bundle of hundreds of strands, so you need quite a few satellites to replace one cable.
yesterday at 10:47 PM
Typical submarine cables at at absolute most 24 strands, more commonly 4, 6, 10 or 12 for modern ones. Terrestrial cables can easily be hundreds and that's quite mundane.
The high capacity in submarine fiber is achieved through DWDM and coherent modulation 100Gbps+ transceivers, not massive parallelism in fiber use.
today at 1:52 AM
Why? compared to the laying cost, an extra 10000 fibers should be pocket change
yesterday at 4:38 PM
Reminds me of the Tom Scott video on the cable singe that leverages the moiré effect:
https://www.youtube.com/watch?v=d99_h30swtM
yesterday at 5:43 PM