A mystery that began as tensions between the U.S. and the Soviet Union were coming to a boiling point.

這個謎團的起因是美國和蘇聯之間的緊張局勢即將達到沸點。

During the Cold War, different branches of the American military set up stations around the world to monitor Soviet activity, including in the deep ocean.

冷戰期間，美國軍方的不同部門在世界各地建立了監測站，以監視蘇聯的活動，包括在深海的活動。

SOSIS, a classified network of passive very specific goal in mind, to detect Soviet submarines.

SOSIS 是一個保密網絡，其被動目標非常明確，即探測蘇聯潛艇。

But when the Cold War fizzled out in 1990, the Navy decided to change gears.

但是，當冷戰在 1990 年逐漸消退時，海軍決定改弦更張。

It offered scientists at NOAA the opportunity to use their sonar arrays in the Pacific to monitor environmental conditions.

它為海洋大氣局的科學家們提供了利用其在太平洋的聲納陣列監測環境狀況的機會。

It would give researchers the ability to monitor volcanic activity in the Pacific Northwest and study hydrothermal systems.

它將使研究人員有能力監測西北太平洋地區的火山活動並研究熱液系統。

By 1991, NOAA was fully integrated into the system and began recording data.

到 1991 年，NOAA 已完全融入該系統，並開始記錄數據。

But as soon as they started listening, they started hearing a strange sound.

但他們剛開始傾聽，就聽到了一種奇怪的聲音。

The repeating pulses sound almost like an underwater car alarm, or some strange geologic process that we don't understand.

重複脈衝的聲音聽起來就像是水下汽車警報器，或者是我們不瞭解的某種奇怪的地質過程。

The noise is so loud that it can be recorded throughout the Pacific.

噪音非常大，整個太平洋都能聽到。

And more than 30 years later, it still hasn't stopped.

30 多年過去了，這種情況仍未停止。

It was named upsweep, but maybe sound from hell would have been more fitting.

它被命名為 upsweep，但也許來自地獄的聲音更貼切。

And as spooky as this was, it was only the start of the strange sounds the scientists recorded.

雖然這很詭異，但這只是科學家們記錄到的奇怪聲音的開始。

Next came the whistle, and Julia.

接著是哨聲和朱莉婭。

And the loudest sound of all came to be known as the bloop.

最響亮的聲音就是 "嘭嘭 "聲。

This sound was picked up by placed more than 3,000 kilometers apart.

這種聲音被相隔 3000 多公里的地方接收到。

What was going on in the ocean?

海洋裡發生了什麼？

Were the scientists picking up clandestine military exercises?

科學家們發現了祕密軍事演習嗎？

Giant squid doing something weird?

巨型烏賊在做怪事？

Undiscovered sea monsters?

未被發現的海怪？

It turns out the ocean is much, much noisier than we'd ever guessed.

事實證明，海洋比我們想象的要嘈雜得多。

As more research stations have placed hydrophones across the oceans, we've gotten better at identifying certain things.

隨著越來越多的研究站在大洋上安裝水聽器，我們在識別某些東西方面的能力也越來越強。

But there is still so much we still can't identify.

但我們仍有很多東西無法確認。

Why does the ocean have so many strange sounds?

為什麼海洋有這麼多奇怪的聲音？

And why have scientists managed to guess at the origins of certain sounds while others remain an utter mystery?

為什麼科學家能夠猜測出某些聲音的起源，而另一些聲音的起源卻仍然是個謎呢？

At its most basic level, sound is compressed energy, a vibrating wave.

在最基本的層面上，聲音是壓縮的能量，是一種振動波。

It requires a substance to travel through, whether that's solid, liquid, or gas.

它需要一種物質穿過，無論是固體、液體還是氣體。

Like the iconic tagline for the movie Alien says, in space no one can hear you scream.

正如電影《異形》的標誌性標語所說，在太空中，沒人能聽到你的尖叫。

That's because space is a vacuum with an extremely low density of particles available for sound to vibrate through.

這是因為太空是真空的，可供聲音振動的粒子密度極低。

Given the importance of particles in carrying sound, it's probably no surprise that noise travels differently above water and below.

鑑於顆粒在傳播聲音方面的重要性，噪音在水上和水下的傳播方式不同也就不足為奇了。

Water molecules are much more tightly packed than gases, making the ocean about 800 times denser than air.

水分子比氣體緊密得多，是以海洋的密度是空氣的 800 倍。

So when a sound wave vibrates a molecule of water, the vibration gets passed on much faster to the next molecule than when sound moves through air.

是以，當聲波振動水分子時，振動傳遞到下一個分子的速度要比聲音在空氣中傳播快得多。

In fact, sound travels almost five times faster in water than in air.

事實上，聲音在水中的傳播速度幾乎是空氣中的五倍。

But the distance that sound travels in water relies on more than just speed.

但是，聲音在水中傳播的距離不僅僅取決於速度。

And that's where things get complicated.

這就是事情變得複雜的地方。

The physical and chemical properties of the ocean all contribute to how sound waves move.

海洋的物理和化學特性都會影響聲波的運動。

Temperature, salinity, and pressure all play a role.

溫度、鹽度和壓力都會產生影響。

Near the ocean surface is the lowest pressure, but the highest temperature.

海洋表面附近的氣壓最低，但溫度最高。

And the high temperature causes sound to move faster.

高溫會使聲音傳播得更快。

In the deepest parts of the ocean is the coldest temperature, but the highest pressure.

海洋最深處的溫度最低，但氣壓最高。

And in that case, the high pressure is what causes sound to move faster.

在這種情況下，高壓會使聲音傳播得更快。

But between a few hundred and a thousand meters is a zone of low temperature and relatively low pressure, where the speed of sound is minimal.

但是，在幾百米到一千米之間是一個低溫和相對低壓的區域，在這裡聲速是最小的。

A sound wave in this channel will naturally radiate in all directions.

聲波在這個通道中會自然地向四面八方輻射。

But when it travels into shallower or deeper water outside of the channel, it encounters an area with faster sound transmission.

但當它進入航道外較淺水區或深水區時，就會遇到聲波傳播速度較快的區域。

And when the sound waves encounter this, the waves tend to be refracted or bent back towards the of lower speed without losing much energy.

當聲波遇到這種情況時，聲波往往會折射或彎曲，返回到速度較低的地方，而不會損失太多能量。

This means that sounds tend to stay in this channel, traveling slowly over great distances.

這意味著聲音往往會停留在這個通道中，緩慢地傳播很遠的距離。

This zone is known as the so far channel, or the deep sound channel.

這一區域被稱為 "遠距離通道 "或 "深層聲道"。

It preserves sound so well that in an experiment from 1960, the sound of explosives detonated in the waters off the coast of Australia were heard all the way in Bermuda, nearly 20,000 kilometers away.

它能很好地保存聲音，以至於在 1960 年的一次實驗中，在澳洲海岸附近水域引爆炸藥的聲音在近 2 萬公里外的百慕大都能聽到。

Thanks to the so far channel, scientists can monitor everything from underwater volcanoes to earthquakes.

藉助迄今為止的通道，科學家們可以監測從水下火山到地震的所有情況。

And as scientists have learned about the way sound moves in the ocean, they've been able to listen in more and more.

隨著科學家們對聲音在海洋中移動方式的瞭解，他們能夠聆聽到越來越多的聲音。

They've placed hydrophones and other passive recording systems all around the world.

他們在世界各地安置了水聽器和其他無源記錄系統。

And it turns out the ocean is a very noisy place.

原來，大海是一個非常嘈雜的地方。

As of the most recent surveys, there are 126 marine mammal species, around 35,000 known fish species, and nearly 250,000 marine invertebrates.

在最近的調查中，共有 126 種海洋哺乳動物、約 35,000 種已知魚類和近 250,000 種海洋無脊椎動物。

And a lot of these creatures are soniferous, or sound producing.

這些生物中有很多都能發出聲音。

We didn't even always know that whales could sing.

我們甚至並不總是知道鯨魚會唱歌。

But today we know that all marine mammal species make sounds, either echolocation for hunting or sounds for communication.

但今天我們知道，所有海洋哺乳動物物種都會發出聲音，或是通過回聲定位來捕獵，或是通過聲音來交流。

In fact, certain baleen whales communicate at frequencies that are specifically suited to so far, allowing them to stay in touch over long distances while migrating.

事實上，某些鬚鯨的通信頻率特別適合遠距離通信，使它們能夠在遷徙過程中保持長距離聯繫。

But in at least one case, the cetacean communication seemed to go wrong.

但至少有一次，鯨目動物的交流似乎出了問題。

In 1989, researchers picked up calls from the North Pacific that sounded like a blue or fin whale.

1989 年，研究人員從北太平洋捕捉到了聽起來像藍鯨或長鬚鯨的叫聲。

But instead of being in the normal 15 to 25 Hertz range, this whale was calling at 52 Hertz, a much higher frequency.

但是，這條鯨魚的叫聲頻率不是正常的 15 到 25 赫茲，而是 52 赫茲，頻率要高得多。

Nicknamed 52, the cetacean earned the moniker of the loneliest whale, because scientists believed its wrongly pitched calls might mean it had trouble interacting with its species.

這隻鯨魚的暱稱是 "52"，它獲得了 "最孤獨鯨魚 "的稱號，因為科學家認為它錯誤的叫聲可能意味著它很難與同類交流。

The unusual whale's voice continued to be picked up for decades, leading scientists to speculate that it was a malformation, or maybe that the whale was some kind of hybrid between two species that don't normally mate.

這種不尋常的鯨魚的聲音幾十年來一直被人們聽到，這讓科學家們猜測這是一種畸形，也可能是兩種通常不交配的鯨魚之間的某種雜交。

It's a mystery that still hasn't been definitively solved to this day, though some now think there may be more than one whale communicating at this frequency. 52 might not be the loneliest whale after all.

儘管現在有人認為可能不止一條鯨魚在用這個頻率進行交流，但這個謎團至今仍未徹底解開。52 號鯨魚也許並不是最孤獨的鯨魚。

And mysterious whales are only the start when it comes to see creatures making strange sounds.

神祕的鯨魚只是看到生物發出奇怪聲音的開始。

Forget Cthulhu, there are probably hundreds of species of fish and invertebrates who chatter away without us being able to identify them.

拋開 Cthulhu 不說，可能有數百種魚類和無脊椎動物在我們無法識別的情況下喋喋不休。

For example, it took years for scientists to figure out that the crackling sound that they heard near coral reefs was made by snapping shrimp, whose claws produce a loud snap when they snap them shut fast enough to create a projectile, lethal bubble they use for hunting.

例如，科學家花了數年時間才發現，他們在珊瑚礁附近聽到的噼啪聲是由鱷蝦發出的，當鱷蝦的爪子以足夠快的速度合攏時，就會發出響亮的 "啪 "聲，從而產生一種彈射物，這是它們用來捕獵的致命氣泡。

There are also daily choruses in coral reefs around the world, when the intensity of sound increases by two to three orders of magnitude after sunset and just before sunrise.

世界各地的珊瑚礁每天也會發生合唱，日落後和日出前，聲音強度會增加兩到三個數量級。

Scientists don't know how many species contribute to this sudden cacophony, but in one case they discovered that a major contributor of the noise around New Zealand came from hungry sea urchins.

科學家們不知道有多少物種造成了這種突如其來的噪音，但有一次他們發現，紐西蘭周圍的噪音主要來自飢餓的海膽。

Their skeleton was acting as an amplifier for the sound of their chomping.

它們的骨架充當了它們咀嚼聲的放大器。

The ocean is chock-full of organisms who are making noises, whether it's because of their hunting or their feeding or just because they want to stay in touch with friends.

海洋中有許多生物都在發出聲音，不管是因為捕食還是覓食，或者只是因為它們想與朋友保持聯繫。

And all of that noise means there are a lot of sounds we haven't identified yet.

所有這些噪音意味著還有很多我們尚未識別的聲音。

But on top of the organisms are all of the geological processes happening underwater, and that adds yet another layer of complication.

但是，除了生物之外，水下還發生著各種地質過程，這又增加了一層複雜性。

As we've talked about in previous videos about underwater volcanoes, the seafloor is a hotbed of geologic activity.

正如我們在之前關於海底火山的視頻中所說，海底是地質活動的溫床。

Tectonic plates spreading apart or subducting under each other create magma and earthquakes and even violent eruptions.

構造板塊相互分離或俯衝會產生岩漿和地震，甚至劇烈噴發。

All these geologic processes produce sounds that can be picked up on hydrophones.

所有這些地質過程都會產生水聽器可以捕捉到的聲音。

But there are also massive glaciers and icebergs in the North and South Poles, and those huge slow-moving structures also create noise.

但是，南北兩極也有巨大的冰川和冰山，這些緩慢移動的巨大結構也會產生噪音。

In fact, they're now thought to be responsible for multiple noises that were previously unidentified.

事實上，現在人們認為它們對以前無法確定的多種噪音負有責任。

Remember the bloop, the loudest ocean sound that's ever been recorded?

還記得有史以來最響亮的海洋聲音 "啵 "嗎？

Researchers heard it in 1997 on hydrophones scattered across the Pacific.

1997 年，研究人員通過散佈在太平洋上的水聽器聽到了它的聲音。

They were trying to listen to underwater volcanic activity, and this noise was nothing like the sounds they'd been hearing.

他們試圖傾聽水下火山活動的聲音，而這種聲音與他們一直聽到的聲音完全不同。

For years, theories abounded.

多年來，各種理論層出不窮。

Maybe it was a secret military exercise, maybe it was a giant squid, maybe it was a really really loud whale, or it could be an undiscovered deep-sea creature.

也許是一次祕密軍事演習，也許是一隻巨大的烏賊，也許是一條非常非常吵鬧的鯨魚，也可能是一種未被發現的深海生物。

Then in 2005, researchers put hydrophones closer to Antarctica and captured the bizarre noise again.

2005 年，研究人員把水聽器放到了離南極洲更近的地方，再次捕捉到了這種怪異的聲音。

It was an ice quake, the incredibly loud sound of an iceberg cracking and breaking away from the Antarctic glacier.

那是冰震，是冰山裂開、脫離南極冰川發出的巨大聲響。

The more scientists listened to the movement of ice, the more they realized it explained other mysterious sounds too.

科學家們對冰的運動聽得越多，就越發現它也能解釋其他神祕的聲音。

The noise Julia is now thought to have been a large iceberg running aground, its bottom slowly scraped away by the seafloor.

現在人們認為，"朱麗亞號 "是一座擱淺的大冰山，它的底部慢慢地被海底颳去。

But even as researchers have expanded their arrays, certain sounds have remained a mystery.

但是，即使研究人員擴大了陣列，某些聲音仍然是個謎。

That's the case for upsweep, the repeated lifting noise that scientists have been hearing around the Pacific for more than 30 years.

科學家們 30 多年來在太平洋周圍聽到的反覆升降噪音就是這種情況。

Although it's getting quieter, the sound can still be heard.

雖然聲音越來越小，但還是能聽到。

And even weirder, it fluctuates seasonally, its intensity peaking in the spring and fall.

更奇怪的是，它還會隨季節波動，其強度在春季和秋季達到頂峰。

The origin point of the sound is thought to be in an area of activity, but we still don't know what it is.

聲音的發源地被認為是一個活動區域，但我們仍然不知道它是什麼。

It's yet another mystery of the deep ocean, one that we may never solve.

這是深海的又一個謎，我們可能永遠也解不開。

Despite all the things we don't know yet about underwater sounds, there are a few key things we're becoming more and more aware of.

儘管我們對水下聲音還有很多不瞭解的地方，但有幾個關鍵點我們正變得越來越清楚。

First, a lot of organisms like living in noisy neighborhoods.

首先，很多生物喜歡生活在嘈雜的社區。

When researchers played recordings of healthier reefs around reefs that had been degraded, 50% more fish ended up repopulating the degraded reefs than those without any recordings.

當研究人員在已退化的珊瑚礁周圍播放較健康珊瑚礁的錄音時，與沒有任何錄音的珊瑚礁相比，最終在已退化的珊瑚礁上重新繁殖的魚類多了 50%。

The same preferences are true of coral larvae, who spend an initial life phase away from the reefs before settling back into them to grow into coral structures.

珊瑚幼蟲也有同樣的喜好，它們在遠離珊瑚礁的地方度過最初的生命階段，然後再回到珊瑚礁定居，成長為珊瑚結構。

Research like this seems to prove that noise plays a crucial role in these coastal communities.

這樣的研究似乎證明，噪音在這些沿海社區起著至關重要的作用。

But the other thing researchers have proved is that humans are increasingly contributing to ocean noises, and we do not make the kind of noise that aquatic species appreciate.

但研究人員已經證明的另一件事是，人類對海洋噪音的貢獻越來越大，而我們發出的噪音並不為水生物種所欣賞。

Motorboat noise around reefs has a negative impact on fish reproduction, and shipping traffic definitely causes issues for whales, who hunt and communicate using frequencies that are similar to the noises the ships make.

珊瑚礁周圍的摩托艇噪音會對魚類繁殖產生負面影響，而航運交通肯定會給鯨魚帶來問題，因為鯨魚捕食和交流的頻率與船隻發出的噪音相似。

What's more, climate change is driving increasingly high temperatures in the ocean, and that heating means that sounds will travel differently, which could create yet another problem for species that use sound to hunt and communicate.

此外，氣候變化導致海洋溫度越來越高，這種升溫意味著聲音的傳播方式將發生變化，這可能會給利用聲音捕食和交流的物種帶來另一個問題。

So while the oceans might be naturally noisy places, humans are changing the kinds of noise pretty drastically.

是以，雖然海洋可能是一個自然嘈雜的地方，但人類正在極大地改變噪音的種類。

And that means it can be sometimes even harder to figure out the source of mysterious sounds.

這意味著有時要弄清神祕聲音的來源可能更加困難。

But the more we listen, the more we find, and the better we understand the way that sound contributes to the well-being of aquatic organisms.

但是，我們聽得越多，發現得越多，也就越能理解聲音對水生生物福祉的貢獻。

So scientists will keep eavesdropping on fishes and volcanoes and icebergs in hopes that we'll figure out what all is going on in that vast watery expanse.

是以，科學家們將繼續竊聽魚類、火山和冰山的聲音，希望我們能搞清楚那片廣袤的水域中到底發生了什麼。

Whenever there's a big mystery, like these mysterious ocean sounds, or even like recent UFO sightings, the first thing everyone does is run to the scientists for answers.

每當出現一個大謎團，比如這些神祕的海洋聲音，甚至像最近的不明飛行物目擊事件，大家做的第一件事就是向科學家尋求答案。

Everyone loves to speculate, but it's usually physics and math that have the answers.

每個人都喜歡猜測，但通常只有物理學和數學才有答案。

Some might say that trying to actually do science on these mysteries ruins the fun, but I disagree.

有些人可能會說，試圖真正對這些謎團進行科學研究會破壞樂趣，但我不同意。

What's more satisfying than finding the answer to a puzzle that has had everyone stumped for years?

有什麼比找到一個讓大家困惑多年的謎題的答案更令人滿意的呢？

And what is Earth if not a big rock full of mysteries?

如果地球不是一塊充滿神祕的大石頭，那它又是什麼呢？

And what is science if not the way we solve those mysteries?

如果科學不是我們解開這些謎團的方法，那科學又是什麼呢？

With the tools of physics and math under your belt, anyone can be a real-life mystery solver.

只要掌握物理和數學工具，任何人都可以成為現實生活中的解謎者。

And surprisingly, there's a free and easy way to practice these skills.

令人驚訝的是，有一種免費而簡單的方法可以練習這些技能。

Brilliant has so many courses on subjects that reveal the physics of the real world and get you thinking about the phenomena we all experience but may not understand.

Brilliant 有許多揭示現實世界物理學的課程，讓你思考我們都經歷過但可能不瞭解的現象。

Brilliant is the best way to learn math, data science, and computer science interactively.

Brilliant 是互動學習數學、數據科學和計算機科學的最佳方式。

I've always struggled with lectures and textbooks, but Brilliant is an interactive learning environment where lessons are structured around things that feel more like games and puzzles than like college coursework.

我一直都很難接受講課和教科書，但 Brilliant 是一個互動式的學習環境，它的課程安排更像是遊戲和謎題，而不是大學課業。

There are levers, slides, and buttons so you can test theories and visualize high-level math and science concepts.

這裡有槓桿、滑梯和按鈕，您可以測試理論並直觀地理解高級數學和科學概念。

The physics of the everyday course has been particularly helpful in visualizing concepts that I see all the time but never fully understood.

日常物理課程對於我直觀地理解那些我經常看到但從未完全理解的概念特別有幫助。

It helps you investigate things like household objects, buildings, bridges, and weather patterns, unraveling the mysteries of the everyday.

它可以幫助你調查家居用品、建築物、橋樑和天氣模式等事物，揭開日常事物的神祕面紗。

Maybe the way toilets work isn't mysterious to everyone, but it was to me.

也許廁所的工作方式對每個人來說並不神祕，但對我來說卻是如此。

And even if you do know how toilets work, I guarantee there is something in this 38-part lesson that will surprise you.

即使你知道廁所是如何工作的，我保證這 38 節課中也會有讓你大吃一驚的內容。

Brilliant has thousands of lessons like this, from foundational to advanced math, to AI, data science, neural networks, and more, with new lessons added monthly.

Brilliant 有成千上萬這樣的課程，從基礎數學到高級數學，再到人工智能、數據科學、神經網絡等，而且每月都有新課程加入。

So to better learn how to confidently navigate this world of overwhelming numbers, and to try everything Brilliant has to offer, free for a full 30 days, visit Brilliant.org slash RealScience or click on the link in the description.

是以，要想更好地學習如何自信地駕馭這個充滿壓倒性數字的世界，並在整整 30 天內免費試用 Brilliant 提供的一切服務，請訪問 Brilliant.org slash RealScience 或點擊說明中的鏈接。

The first 200 people will get 20% off Brilliant's annual premium subscription, and every sign-up helps this channel.

前 200 名註冊者可享受 Brilliant 年度高級訂閱八折優惠，每一位註冊者都將對本頻道有所幫助。