Discussion in 'science and environment' started by EastEnder, Jun 16, 2006.
It's basically one bloody long volcano, how do they get cables over it without them melting?
You mean there are cables than run under the atlantic ???
Well they don't use them for anything now- sattelites innit.
No - still use cables loads.
wicked, so if you get lost diving you can just follow them home
The vast majority of internet traffic goes round the world via cables.
Would cost a bomb to do it all with satellites, not to mention the lack of available bandwidth...
They build in a few feet of extra cable too don't they - to account for the atlantic getting bigger every second.
quite possibly thy don't go all the way down but float midway?
First one was August 5, 1858
Do try to keep up
It's not one long volcano, anymore than the Pacific's Ring of Fire. One just goes round the volcanoes.
Your actual continental drift takes place in rift valleys which needn't be volcanic.
Plus which there's actually quite a lot of redundant cable out there, thanks to self-healing rings.
Some gratuitous bandwidth porn on the latest transatlantic cable system, TAT-14:
I used to live in Porthcurno, Cornwall which is where the transatlantic cables drop off the end of Britain. Occasionalyl they would dig up an entire beach to lay a new one, and then join it to a huge floating cable-rig just out to sea.
I've got some photos somewhere that I'll look out if I can find them. In response to the OP I think it's mostly insulation and lots of spare cable. Don't know how they deal with volcanoes though...
thats a bit clever
There's a British ship that fixes these cables, I saw it on discovery - it is basically exactly how they used to fix it in the olde dayes but with better ships
On this subsect - Neal Stephenson, the sci-fi author did an article a few years back on his trip around the world looking at the cables which wire our world.
Its wonderfully nerdy, but fascinating at the same time - the whole story is fascinating - hi highly recommend it - print it off and take a read some time:
Eh? TAT-14 is made out of 64 dual redundant fibres each operating at 10GB/sec, TAT-12/13 (each half of the ring) are made out of 12 fibres operating at 2.5 GB/sec, both those cables have landing in the UK and in France. Most UK cables come ashore on Irelands Atlantic cost near Shannon and they all carry vastly more data with far better latency than any satellite transmission.
I think that you think that the Mid-Atlantic ridge (MAR) is a far more exciting place than it is in reality. One long volcano it is and also in continuous eruption but under water this is a slow affair and it isn't happening all the way along the ridge all the time, or even most of the time.
The cable breaks that do occur are more common on the slopes down to the abyssal plain where slides may rip of stretch the cable or from Anchor scars on in less than 100m of water.
Ok, I'm just trying to explain how inactive the 2 centimetres per year that the MAR extends looks in real life. Here is a photo looking down the ridge at a point where it is on the surface in Iceland. The road has been there a while is my guess.
Even when it does erupt, and you can find some pretty incredible linear eruptions on occasion in Iceland when a split like that opens in the Earth's surface at the bottom of the ocean it is a much less impressive affair.
Even ocean bottom eruptions is over egging the pudding though, most of the extension happens by lava infilling cracks deep in the crust and small earthquake events and slippage tilting and rotating blocks higher in the crust.
When these cables are laid there are extensive surveys of the areas where there is risk and there is slack given to the cable at points where there is movement in the ocean floor.
really enjoying reading this at the moment. I wanna become a cable layer!
There must be some spaces, or some areas of dormant volcanoes, otherwise, there'd be a big line of bubbling hot water running right down the middle of the atlantic, above all those volcanoes on the ocean floor.
Can you imagine how heavy two thousand miles of cable would be?
The operative word is "float" in that sentence, how heavy do you think a fully laden oil tanker is? Weight is not a insurmountable problem in water
Of course i think you're right, they don't float, but they could.
Oh fucking hell, now I'm wasting the whole working day reading Stephenson
You understand about buoyancy. A ship floats due to its shape, which gives it buoyancy. If you took the weight of a ship, and turned it into cable and threw it into the water, the whole thing would sink right to the bottom.
Wow! Thanks for posting that - a great read!
What an amazing thread, im speechless....
Yes and we both know just how easy it is to make floatation tanks.
photo by Taryn Simon (recently exhibited at photogs gallery)
"Transatlantic Submarine Cables Reaching Land
VSNL International, Avon, NJ
These VSNL submarine telecommunications cables extend 8,037.4 miles across the Atlantic Ocean. Capable of transmitting over 60 million simultaneous voice conversations, these underwater fiber-optic cables stretch from Saunton Sands in the United Kingdom to the coast of New Jersey. The cables run below ground and emerge directly into the VSNL International headquarters, where signals are amplified and split into distinctive wavelengths enabling transatlantic phone calls and internet transmissions.
Underwater fiber-optic cables are laid along the ocean’s floor by specially designed ships. Cables are buried as they approach shore and armored to protect against undersea landslides, marine life (sharks, in particular), and fishing equipment. Fishermen are advised of cable locations as hooking one can interfere with international communication services as well as sink a boat.
VSNL operates one of 14 submarine cable systems connected to the continental United States. Exchanges originating in the US are combined and enhanced before broadcast and transmission across the Atlantic. As of 2005, submarine cables link all the world’s continents except Antarctica.
Nowadays carrier grade fibre tends to run SDH and the ring topology also allows you to have dual entry points into a building for additional redundancy.
SDH is the dogs Shame its big boys toys
Correct. Satellite and cable actually do two different things (although there is clearly some overlap).
If you want to link two high density points, like London and New York, cable is perfect
If you want to provide low density service over a wide area, you use satellite.
So a phone call to New York would go on the atlantic cable, whilst providing services to remote parts of Africa is a job for satellite.
Sometimes a call will go via both, for example if you call Sydney from that remote african village your call would proberbly be sent via satellite to Cape Town, then squirted down a cable to Oz.
Check out http://en.wikipedia.org/wiki/How_the_World_Was_One:_Beyond_the_Global_Village it is a brilliant book.
Halfway thru the article, fucking great...
28K KM tho...that's almost geostationary orbit...
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