1月15日，南半球岛国汤加的一座火山突然爆发，摧毁了连接汤加与世界的海底光缆，使整个国家瞬间失去网络连接。
那么，什么是海底光缆？为什么它在互联网时代如此重要？海底光缆有被摧毁的风险，有没有什么替代方案？这篇整合文章或许能解答你的问题。
1.海底光缆：互联网“突破国界”的道路
A submarine cable is a cable laid on the sea bed between land-based stations to carry telecommunication signals across stretches of ocean and sea. Subsequent generations of cables carried telephone traffic, then data communications traffic. Modern cables use optical fibre technology to carry digital data, which includes telephone, Internet and private data traffic.
海底线缆，铺设于不同大陆之间的海床上，连接着陆地基站。它被用来进行跨海信号传输。随着技术更迭，海底线缆传输的信息从电报、电话，直到数据通信流量。现代海底线缆使用光纤技术来传输数字数据，包括电话信号、互联网信息和私人数据。
Subsea cables are the lifeline of a modern connected world. Almost everything that we do on the internet and the phone—calling, texting, running a software application, downloading or uploading information, streaming—needs the help of a subsea cable, hundreds of miles under the sea.
海底光缆是现代网络世界的生命线。我们利用现代信息科技做的几乎所有事情——比如打电话、发短信、使用APP、下载资料、发布动态、听歌看剧——都离不开海底这数十万公里光缆的帮助。
预计到2023年时的全球海底光缆地图
A standard cable is expected to last for an average of 25 years, but unpredictable conditions at sea mean that accidents can occur. Seaquakes, storms, and even careless sailing or anchoring by ships can break the cables.
海底电缆的平均预期寿命为25年。但海洋条件的变化不可预测，海底光缆随时都可能发生事故。海底地震、风暴，甚至只是船只航行时的失误都可能破坏光缆。
*注：汤加火山爆发正是因为损坏了海底光缆而导致了全国网络中断，修复过程预计需要四周之久。
When this happens, it takes days or weeks to get them up and working again. Engineers first have to locate the faulty cable onshore using advanced underwater technology. Next, a repair ship is sent out to the ocean to the repair site. The faulty cable is then fished onboard using a grapple reeling device and is then replaced with a brand new fiber optic cable.
当光缆发生事故时，往往需要数天甚至几周的时间才能让它重新开始工作。工程师需要用先进的水下探测技术，在陆地上定位好光缆故障的位置；随后，一艘修理船会驶达修理现场。修理船上有特制的抓斗卷绕装置，将海底的故障光缆回收，然后用新的光缆进行替换。
This is why when a subsea cable snaps, or when it is under maintenance, it makes the news.
修复的困难，正是海底光缆故障受到巨大关注的原因。
2.一项精巧而庞大的工程
Modern cables are typically about 25 mm in diameter and weigh around 1.4 tons per kilometer for the deep-sea sections which comprise the majority of the run, although larger and heavier cables are used for shallow-water sections near shore.
现代光缆（本体）直径一般约25毫米，每千米重1.4吨——这是安置于深海区的大部分海底光缆的规格。在靠近海岸的浅水区，光缆会更粗、更重。*是因为靠近海岸的区域受到水体流动、海洋生物及极端天气的影响更为严重。
Submarine cables are laid down by using specially-modified ships that carry the submarine cable on board and slowly lay it out on the seabed as per the plans given by the cable operator. The ships can carry with them up to 2,000km-length of cable.
海底光缆的铺设由一种经过特殊改装的船只完成，它将光缆运输到铺设地点，根据运营商的计划将其缓慢置于海底。一艘船一次可以携带长达2000公里的光缆。
Cable ships can do anywhere from 100-150km of cable laying per day. Newer ships and ploughs now do about 200km of cable laying per day.
光缆船每天可以进行100-150公里的光缆铺设。新生产的船舶和犁的铺设效率可达每日约200公里。
光缆船在铺设光缆
一幅描绘光缆船工作场景的画作，作者为美籍亚裔插画师Ping Zhu。
One of the greatest enemies of submarine cables is the teredo, an aqueous worm. These worms in some parts of the sea particularly near land are very abundant, and can work their way through the outer covering of the cable and interrupt communication. To guard against this, the core of present-day cables is covered with brass tape. This brass tape is impervious to the assault of the teredo. But in the deep water there is very little to injure submarine cables.
海底光缆的一个最大敌人是一种名为“teredo”的海洋蠕虫。这些蠕虫在陆地附近尤为丰富。它们能够钻破普通光缆的表层，中断通讯。为了防止这种情况的发生，现代电缆的内部通常会加上一层黄铜胶带，避免蠕虫攻击。不过在深水区，几乎没有什么生物会威胁到光缆。
3.可能的替代方案：马斯克的“星链”雄心
Starlink is SpaceX’s plan to build an interconnected internet network with thousands of satellites — known in the space industry as a constellation. It’s designed to deliver high-speed internet to consumers anywhere on the planet. SpaceX has about 2,000 Starlink satellites in orbit.
星链（Starlink）是美国商业航天公司SpaceX的一项计划，目的是建立一个拥有数千颗卫星的低空互联网通信网络——这种众多卫星共同工作的形式，在航天工业中被叫做“星座”。它旨在为地球上任何地方的消费者提供高速的互联网服务。目前，SpaceX有约2000颗在轨的星链卫星。
示意图
The Starlink project began in January 2015 and has expanded its footprint both across the world, in terms of projected availability, and all over the planet, in terms of the number of satellites.
星链项目始于2015年1月。至今，无论是在卫星数量上，还是在理论可用性上，它都扩展到了全球各地。
In December 2020, Starlink got a boost when SpaceX won US$885 million in federal subsidies from the Federal Communications Commission (FCC), a US government agency, to help bring broadband connectivity to parts of the US with little to no internet connectivity.
2020年12月，美国联邦通信委员会（FCC）向SpaceX提供了8.85亿美元的联邦补贴，推动其将星链服务扩展到美国部分网络不畅的地区。
星链用户的家用地面接收器，形似过去用来接收电视信号的“卫星锅盖”（蝶形电视接收器）
This Elon Musk’s company recently gave an update on its Starlink internet service, as the company launched more satellites into orbit.
近期，随着新一批卫星发射升空，这个由埃隆·马斯克掌控的公司公布了星链计划的最新进展。
SpaceX engineer Jessie Anderson said during a webcast of the company’s first launch of the year that Starlink now has more than 145,000 users in 25 countries around the world. That’s up from 140,000 users in early November but represents a slowdown in user growth.
在SpaceX 2022年首次发射的现场直播中，工程师杰西·安德森表示，星链目前已在全球25个国家拥有超过14.5万名用户。相较去年11月初（14万用户），这个数字增加了，但用户增长速度有所放缓。
太空中的星链卫星实拍
The company launched a Falcon 9 rocket from Florida on Jan 4, carrying 49 Starlink satellites toward orbit.
1月6日，SpaceX在佛罗里达州发射了一枚猎鹰9号火箭，将49颗新的星链卫星送入了轨道。
难点词汇与表达
diametern. 直径；对径 a straight line going from one side of a circle or any other round object to the other side, passing through the centre
例 The dome is 42.3 metres in diameter.
ploughn. 犁 a large farming tool with sharp blades that is pulled across the soil to turn it over, usually before seeds are planted.
例 There are new tractors and new ploughs in the machinery lot.
aqueous adj. 水的；含水的；水状的containing water; like water
例 ...an aqueous solution containing various sodium salts.
constellation n. 星座 a group of stars which form a pattern and have a name.
例 This planet sits in the southern constellation of Fornax.
原文链接
https://www.independent.co.uk/news/science/how-are-major-undersea-cables-laid-in-the-ocean-9993232.html
https://web.archive.org/web/20160526231647/http://www.techteledata.com/how-submarine-cables-are-made-laid-operated-and-repaired/
https://www.makeuseof.com/what-are-subsea-cables/
https://www.cnbc.com/2022/01/06/spacex-starlink-internet-service-has-more-than-145000-users-so-far.html
编译 | 黄怡涛
排版 | 黄怡涛
