One foggy morning in 1884, the British steamer 'Rumney' crashed into the French ship 'Frigorifique.'
在1884年一个雾蒙蒙的早晨，英国蒸汽船罗姆尼号撞上了法国费格里齐号。
Seeing their ship filling with water, the French crew climbed aboard the 'Rumney.'
发现船舱进水后，法国船员迅速登上了罗姆尼号。
But as they sailed towards the nearest port, a silent form suddenly emerged from the fog: the abandoned 'Frigorifique.'
然而当他们驶向最近的港口时，被抛弃的费格里齐号突然从寂静的迷雾中浮现出来。
It was too late to turn, and the impact was enough to sink the 'Rumney.'
当时船已经来不及掉头，而撞击足以让罗姆尼号沉没。
As the sailors scrambled into the lifeboats,
正当水手们匆忙爬上救生船，
the empty 'Frigorifique' sailed back into the fog, having seemingly taken its revenge.
空船费格里齐号驶回迷雾中，就好像完成了自己的复仇。
In reality, the French sailors had left the engines running,
实际上，法国水手弃船时没有关掉发动机，
and the 'Frigorifique' sailed in a circle before striking the 'Rumney' and finally sinking.
因此费格里齐号在撞上罗姆尼号之前一直在水里做圆周运动，直到沉没。
But its story became one of the many tales of ghost ships, unmanned vessels that apparently sail themselves.
不过这个无人驾驶的船只自己航行的故事成为了众多幽灵船故事中的一个。
And although they've influenced works like 'Dracula' and 'Pirates of the Caribbean,'
虽然这些故事给《德拉库拉》和《加勒比海盗》这样的作品提供了素材，
crewless ships aren't the product of ghostly spirits, just physics at work.
但是无人驾驶的船只与幽灵并没有关系，只不过是物理作用。
One of the most famous ghost ships was the 'Mary Celeste' found sailing the Atlantic in 1872 with no one aboard,
有一艘非常有名的幽灵船，玛丽·塞勒斯特号，在1872年被人发现行驶在大西洋上，船上空无一人，
water in its hold, and lifeboats missing.
船体进水，救生船也不见了。
The discovery of its intact cargo and a captain's log that ended abruptly led to wild rumors and speculation.
船货保存完好，船长的航行日志却突兀的结束，引起了人们无限的猜想。
But the real culprits were two scientific phenomena: buoyancy and fluid dynamics.
而造成这样现象的真正原因是两个科学现象：浮力和流体力学。
Here's how buoyancy works. An object placed in a liquid displaces a certain volume of fluid.
浮力的原理如下。一个放在液体里的物体会排走一定体积的液体。
The liquid in turn exerts an upward buoyant force equal to the weight of the fluid that's been displaced.
于是被排开的液体施加了一个向上的浮力，等同于这些被排开液体的重力。
This phenomenon is called Archimedes's Principle.
这一现象被称为阿基米德原理。
Objects that are less dense than water, such as balsa wood, icebergs, and inflatable rafts always float.
密度小于水的物体，比如软木、冰山、充气式小船，可以一直漂浮在水面上。
That's because the upward buoyant force is always stronger than the downward force of gravity.
这是因为向上的浮力总是大于向下的重力。

But for objects or ships to float when they're made of materials, like steel, that are denser than water,
但像轮船这些由钢铁等材料制成的物体，其密度大于水，为了使其漂浮在水面上，
they must displace a volume of water larger than their weight.
则需要排开比其本身重力更大的水量。
Normally, the water filling a ship's hull would increase its weight and cause it to sink
一般来说，船体进水，船体的重力增加，会导致沉没，
just what the 'Mary Celeste's' crew feared when they abandoned ship.
也就是玛丽·塞勒斯特号船员在弃船时所担心的。
But the sailors didn't account for fluid dynamics.
但是船员们没有考虑到流体力学。
The water stopped flowing at the point of equilibrium, when it reached the same level as the hull.
当涌入的水和外部水面齐平时，就满足了平衡，水也就停止流入了。
As it turned out, the weight of the water wasn't enough to sink the ship
正如事实那样，船体中水的重力不足以让船沉没，
and the 'Mary Celeste' was found a few days later while the unfortunate crew never made it to shore.
因此玛丽·塞勒斯特号在几天之后被人发现，而不幸的船员们却再也没能回到岸上。
Far stranger is the tale of 'A. Ernest Mills,'
A·欧内斯特·米尔斯号的故事更加离奇，
a schooner transporting salt, whose crew watched it sink to the sea floor following a collision.
它是一艘运盐的纵帆船，船员目睹了他们的船被撞后沉入海底。
Yet four days later, it was spotted floating on the surface.
然而四天之后，船被发现漂浮在水面上。
The key to the mystery lay in the ship's heavy cargo of salt.
解开这个谜团的要点在于沉重的货物--盐。
The added weight of the water in the hull made the vessel sink, but as the salt dissolved in the water,
船体进水重力上升导致沉没，但随着盐在水中溶解，
the weight decreased enough that the force of gravity became less than the buoyant force and the ship floated back to the surface.
船体重量的下降足以使得船体的重力小于浮力，因此船又重新回到了水面。
But how do we explain the most enduring aspect of ghost ship legends:
但是我们又该如何解释幽灵船传说经久不衰的话题：
multiple sightings of the same ships hundreds of miles and several years apart?
同一艘船几年后出现在相隔几百英里的地方？
The answer lies in ocean currents, which are like invisible rivers flowing through the ocean.
答案是洋流，它们像是海洋中隐形的河流。
Factors, like temperature, salinity, wind, gravity,
各种因素，比如温度、盐度、风、重力
and the Coriolis effect from the Earth's rotation create a complex system of water movement.
以及地球自传产生的科里奥利效应，共同作用形成一个复杂的海水流动系统。
That applies both at the ocean's surface and deep below.
既影响着海面，也影响着海底。
Sailors have always known about currents, but their patterns weren't well known until recently.
水手们都知道洋流，但是直到近些年来，洋流的具体模式才被人知晓。
In fact, tracking abandoned ships was how scientists determined the shape and speed of the Atlantic Gyre, the Gulf Stream,
事实上，科学家一开始是通过追踪被弃的船来研究大西洋环流和墨西哥湾暖流的速度和形状，
and related currents in the first place.
并且把洋流联系在一起的。
Beginning in 1883, the U.S. Hydrographic Office began collecting monthly data that included navigation hazards,
1883年，美国水文局开始每月收集包括航运风险的数据，
like derelict ships, whose locations were reported by passing vessels.
比如荒废船只的坐标可以由路过的船只上报。
So abandoned ships may not be moved by ghost crews or supernatural curses,
因此，被弃船只可不是受幽灵船员或超自然诅咒控制才航行，
but they are a real and fascinating phenomenon born through the ocean
它们是真实而又迷人的现象，源自海洋，
and kept afloat by powerful, invisible, scientifically studied forces.
因强大、隐形和被科学证实过的力量而漂浮在海洋之上。