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25 Things You Didn't Know About the World's Oceans

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In 2008, the United Nations recognized World Oceans Day on June 8 as a time to celebrate the immense bodies of water that make up roughly 70 percent of the surface of the Earth. The goal of the day is to promote conservation efforts and engage activists in preserving these five crucial areas—the Pacific, Atlantic, Indian, Arctic, and Southern (Antarctic) Oceans—and their inhabitants.

If you don’t know much about the deep blue sea—like why it's not actually blue, for example—check out 25 facts we’ve culled about the world’s largest and most fascinating real estate.

1. THE SUN GIVES IT THAT BLUE TINT.

A look at calm, blue ocean waters
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One of the most indelible features of the oceans is the deep blue waters that are continually churning, rolling, and coming in waves. The color is the result of the sun’s red and orange wavelengths being absorbed by the surface and its blue wavelengths penetrating deeper, giving way to a blue tint. And because those wavelengths can travel further down, the ocean will tend to appear more blue the lower you go. Why isn't water in a glass blue when you're sitting outdoors? There aren't enough molecules to absorb the light.

2. THEY'RE KEEPING THE INTERNET ONLINE.

If you could catch sight of the miles of cable criss-crossing the world’s oceans, it would look like a giant, submerged web. Communications companies maintain international connections by feeding cables down to (hopefully) flat surfaces on the ocean floor. Some require shark-proof layers to prevent predators from biting into your Netflix stream (although the danger of sharks has been vastly overhyped—human activity is a far bigger threat).

3. THE DEEPEST PART IS REALLY, REALLY DEEP.

The Mariana Trench is considered to be the deepest part of the world’s oceans. Inside of the Trench is a valley known as Challenger Deep that extends roughly seven miles (36,070 feet) below the surface. For comparison, the entirety of Mount Everest—at 29,029 feet—could easily be accommodated there. Manned explorations haven’t gone any further than 35,797 feet below the surface, a record set by two oceanographers in 1960. In 2012, filmmaker James Cameron explored roughly the same depths in a solo mission. It’s considered the deepest point on Earth.

4. SOUNDS CAN TRAVEL TO THE DEEPEST EXPLORED AREAS.

Researchers once lowered an underwater microphone called a hydrophone to almost the bottom of the Mariana Trench to see what sounds—if any—it might pick up. After feeling relieved the immense pressure at those depths—about 8 tons per square inch—didn’t implode the equipment, they discovered that sound from earthquakes, passing baleen whales, and other ambient noise was audible.

5. LAKES AND RIVERS LIE BENEATH THE SURFACE.

Some surfaces in the ocean feature sights that don’t seem to make any logical sense—rivers and lakes, some of them miles long, can stretch across the ground even though they’re submerged. How can a body of water exist in a body of water? Water from under the sea floor seeps up and dissolves salt layers, forming depressions. Because the water in the depression is more dense than the water all around it, it settles into the depression and forms a distinct pool.

6. THERE ARE 20 MILLION TONS OF UNTOUCHABLE GOLD IN THE OCEANS.

If you’re hoping to find a fortune in gold prospecting, don’t expect the ocean to cooperate. You may be able to plunder a shipwreck, but you won’t be able to collect much of the 20 million tons of gold estimated to exist in the water. That’s because it’s so diluted that it’s measured in parts per trillion. One liter of seawater might net you a 13-billionth of a gram.

7. WE KNOW MORE THAN YOU MIGHT EXPECT.

A dolphin swims in the ocean
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You might see mentions that we’ve "mapped" more of Mars than we have the Earth’s oceans, but that’s not quite true. Oceanographers have been able to visualize almost 100 percent of the ocean floors, albeit in a resolution that makes it difficult to spot a lot of detail. In that sense, images of Mars and other planets have been able to offer more information because they’re not covered in water that can block radar. Although we haven't explored the vast majority of the oceans first-hand, technology has enabled us to have a rough idea of their layouts.

8. THE BIGGEST WATERFALL ON EARTH IS IN THE ATLANTIC.

Putting Niagara Falls to shame is the Denmark Strait, a waterfall below the Atlantic Ocean that, in terms of water volume, is the equivalent of 2000 of the world’s most notable waterfalls, with cascading liquid pouring 11,500 feet down. The Strait’s cold water on the eastern side is more dense than the warm fluid coming from the west. When the two waters mix, the colder supply sinks, creating a waterfall.

9. WE DON'T KNOW ANYTHING ABOUT MOST OF THE MARINE LIFE.

An octopus is photographed by an ocean photographer
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Size and water pressure conspire to limit our exploration of the oceans, so much so that it’s estimated we’ve identified only one-third of the potential marine life lurking beneath the surface. It’s possible most of those are smaller organisms, but it’s likely that some whales and other mammal species have yet to be discovered. We’re making progress, though: An average of 2000 new species are described each year.

10. MAGELLAN NAMED THE PACIFIC OCEAN.

When Ferdinand Magellan crossed the Atlantic beginning in 1519, he eventually found his way to another body of water—what he dubbed the Pacific, or peaceful, ocean due to the calm surface. He didn’t know it at the time, but the Pacific would eventually be recognized as the largest ocean on the planet at 59 million square miles.

11. THE MOST REMOTE PLACE ON EARTH IS IN THE SOUTH PACIFIC.

Point Nomo is illustrated
Courtesy National Oceanic and Atmospheric Administration

Known as Point Nemo, the area is roughly 1000 equidistant miles away from the coasts of three neighboring islands and so remote that astronauts are often closer to any theoretical occupants than anyone on dry land.

12. MOST VOLCANIC ERUPTIONS ARE UNDERWATER.

Up to 80 percent of volcanic eruptions go unnoticed by land-dwellers. That’s because they’re erupting underwater. An estimated one million volcanoes—some extinct and some very active—spew molten hot lava. Despite the heat, creatures can still be found near their superheated vents. Researchers believe these areas harbor several undiscovered species that are invulnerable to the harsh conditions, including water temperatures up to 750 degrees Fahrenheit.

13. THERE MAY BE BILLIONS IN SUNKEN TREASURE DOWN IN THE DEEP.

A sunken ship sits on the ocean floor
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It’s impossible to offer an accurate estimate of how many shipwrecks and accompanying treasures are lurking in the oceans, but a few people have made an honest effort of it. The National Oceanic and Atmospheric Administration (NOAA) thinks a million sunken ships lurk in the dark; others peg the total value of the unrecovered treasures at $60 billion. So why don’t we hear more stories of watery grave-robbing? Because governments or private parties are likely to make a legal claim to those funds, making an expensive expedition for treasure a gamble at best.

14. THEY KEEP US BREATHING.

Forget all the beauty and wonder of the world’s oceans: At the bare minimum, they’re responsible for supplying us with oxygen. Oceans produce 70 percent of the oxygen supply in the atmosphere thanks to marine plants releasing it as a byproduct of photosynthesis. One phytoplankton, Prochlorococcus, is estimated to be solely responsible for one in every five breaths a human will take.

15. "DEAD ZONES" CAN BE BARREN OF ANY LIFE.

Dark ocean waters can be devoid of life
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One reason pollution is such an issue for oceans: It can rob them of the oxygen needed to support life. When run-off from waste disposal gets into the water, it can feed an overabundance of algae, which then dies, sinks, and as it decomposes, consumes the available oxygen in the water. That creates hypoxic areas, or hot spots with a lack of oxygen. If fish and other marine life don’t find a new space to dwell in, they’re toast.

16. THE FISH ARE EATING A LOT OF PLASTIC.

With over seven million tons of plastic winding up in the ocean each year, it’s inevitable that a lot of it winds up as part of an unwelcome addition to a fish’s diet. For fish in the northern Pacific, researchers at the University of California, San Diego once estimated they swallow between 12,000 and 24,000 tons every year.

17. KEEPING TROPICAL PET FISH MIGHT BE HARMING THE OCEANS.

Colorful tropical fish swim in the water
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Those aquariums in pet stores and dental offices might remind you of marine life, but they might also be having a negative impact. When tropical fish are caught, fishermen use sodium cyanide to make them float out of the reef for easy scooping. While the hope is that it just stuns them, the residue of the chemical can bleach coral reefs and kill scores of other fish.

18. TSUNAMI WAVES CAN REACH 100 FEET...

When waves reach shallow water near land, energy that would normally be dispersed goes up, elongating the wave. A 1958 earthquake and landslide in Alaska generated a tsunami 100 feet high and destroyed all vegetation up to 1720 feet, the largest in recorded history.

19. ...BUT THE BIGGEST WAVES ARE UNDER THE SURFACE.

Called internal waves, these water walls have been found three miles below the surface. The waves are part of water layers with different densities and can reach heights of 800 feet before collapsing. Scientists believe these massive forces can help move heat and nutrients to other areas.

20. WE'RE TRYING TO MAKE THE OCEAN DRINKABLE.

As most everyone knows, drinking salt water is perilous at best and deadly at worst. In a process called desalination, that salt is removed, leaving fresh water. But building facilities and the energy required to process water this way has traditionally been more expensive than sourcing water from potable sources.

21. THE BRISTLEMOUTH IS THE MOST ABUNDANT VERTEBRATE IN THE WORLD.

A bristlemouth snacks on a shrimp
Courtesy National Oceanic and Atmospheric Administration

Not familiar? If you saw one, you’d know. The bristlemouth is a fish a little smaller than your average human finger that has a mouth full of fangs and can glow in the dark. It’s also the most common vertebrate in the world. For comparison? Chickens could number as many as 24 billion on land, while bristlemouths are said to add up to the hundreds of trillions.

22. GIANT KELP GROWS VERY QUICKLY.

Giant kelp, or Macrocystis Pyrifera, is a type of seaweed that experiences an astonishing growth spurt. To reach its usual height of 100 feet, the species can grow up to two feet in a single day.

23. RUBBER DUCKS HAVE HELPED OUR UNDERSTANDING OF THE OCEANS.

A rubber duck floats in the water
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In 1992, a shipment of bath toys was headed from China to the U.S. when the cargo ship dropped a container. More than 28,000 rubber ducks—or duckies, depending on your preference—and other play-animals were dumped into the North Pacific Ocean. Oceanographers tracked where the ducks wound up in order to better understand the water currents, with some landing ashore in Europe and Hawaii. The duck sightings didn’t ease up until the mid-2000s.

24. ANTARCTIC FISH HAVE NATURAL ANTIFREEZE.

Curious how aquatic life can survive the temperatures at the poles? Antifreeze proteins in the fish prevent ice crystals from growing, preventing their blood from being overcome by the chill and allowing it to continue flowing.

25. SEASHELLS DON'T ACTUALLY SOUND LIKE THE OCEAN.

A child holds a seashell up to her ear
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Seashells have long been perceived as the iPods of the sea, tiny little devices that can mimic the static, hissing noise of the water. What they’re actually doing is acting as a resonator, or a cavity that allows sound to vibrate. By holding up the shell to your ear, you’re hearing the ambient noise around you amplified. All that whooshing air typically sounds a lot like the movement of cascading waves. If you can't make it to beach, though, it might be the next best thing.

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Look Up! The Lyrid Meteor Shower Arrives Saturday Night
Scott Butner, Flickr // CC BY-NC-ND 2.0
Scott Butner, Flickr // CC BY-NC-ND 2.0

There is a thin line between Saturday night and Sunday morning, but this weekend, look up and you might see several of them. Between 11:59 p.m. on April 21 and dawn on Sunday, April 22, the Lyrid meteor shower will peak over the Northern Hemisphere. Make some time for the celestial show and you'll see a shooting star streaking across the night sky every few minutes. Here is everything you need to know.

WHAT IS THE LYRID METEOR SHOWER?

Every 415.5 years, the comet Thatcher circles the Sun in a highly eccentric orbit shaped almost like a cat's eye. At its farthest from the Sun, it's billions of miles from Pluto; at its nearest, it swings between the Earth and Mars. (The last time it was near the Earth was in 1861, and it won't be that close again until 2280.) That's quite a journey, and more pressingly, quite a variation in temperature. The closer it gets to the Sun, the more debris it sheds. That debris is what you're seeing when you see a meteor shower: dust-sized particles slamming into the Earth's atmosphere at tens of thousands of miles per hour. In a competition between the two, the Earth is going to win, and "shooting stars" are the result of energy released as the particles are vaporized.

The comet was spotted on April 4, 1861 by A.E. Thatcher, an amateur skywatcher in New York City, earning him kudos from the noted astronomer Sir John Herschel. Clues to the comet's discovery are in its astronomical designation, C/1861 G1. The "C" means it's a long-period comet with an orbit of more than 200 years; "G" stands for the first half of April, and the "1" indicates it was the first comet discovered in that timeframe.

Sightings of the Lyrid meteor shower—named after Lyra, the constellation it appears to originate from—are much older; the first record dates to 7th-century BCE China.

HOW CAN I SEE IT?

Saturday night marks a first quarter Moon (visually half the Moon), which by midnight will have set below the horizon, so it won't wash out the night sky. That's great news—you can expect to see 20 meteors per hour. You're going to need to get away from local light pollution and find truly dark skies, and to completely avoid smartphones, flashlights, car headlights, or dome lights. The goal is to let your eyes adjust totally to the darkness: Find your viewing area, lay out your blanket, lay down, look up, and wait. In an hour, you'll be able to see the night sky with great—and if you've never done this before, surprising—clarity. Don't touch the smartphone or you'll undo all your hard ocular work.

Where is the nearest dark sky to where you live? You can find out on the Dark Site Finder map. And because the shower peaks on a Saturday night, your local astronomy club is very likely going to have an event to celebrate the Lyrids. Looking for a local club? Sky & Telescope has you covered.

WHAT ELSE IS GOING ON UP THERE?

You don't need a telescope to see a meteor shower, but if you bring one, aim it south to find Jupiter. It's the bright, unblinking spot in the sky. With a telescope, you should be able to make out its stripes. Those five stars surrounding it are the constellation Libra. You'll notice also four tiny points of light nearby. Those are the Galilean moons: Io, Europa, Ganymede, and Callisto. When Galileo discovered those moons in 1610, he was able to prove the Copernican model of heliocentricity: that the Earth goes around the Sun.

THERE'S BAD WEATHER HERE! WHAT DO I DO?

First: Don't panic. The shower peaks on the early morning of the 22nd. But it doesn't end that day. You can try again on the 23rd and 24th, though the numbers of meteors will likely diminish. The Lyrids will be back next year, and the year after, and so on. But if you are eager for another show, on May 6, the Eta Aquariids will be at their strongest. The night sky always delivers.

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Can You 'Hear' These Silent GIFs?
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GIFs are silent—otherwise they wouldn't be GIFs. But some people claim to hear distinct noises accompanying certain clips. Check out the GIF below as an example: Do you hear a boom every time the structure hits the ground? If so, you may belong to the 20 to 30 percent of people who experience "visual-evoked auditory response," also known as vEAR.

Researchers from City University London recently published a paper online on the phenomenon in the journal Cortex, the British Psychological Society's Research Digest reports. For their study, they recruited more than 4000 volunteers and 126 paid participants and showed them 24 five-second video clips. Each clip lacked audio, but when asked how they rated the auditory sensation for each video on a scale of 0 to 5, 20 percent of the paid participants rated at least half the videos a 3 or more. The percentage was even higher for the volunteer group.

You can try out the researchers' survey yourself. It takes about 10 minutes.

The likelihood of visual-evoked auditory response, according to the researchers, directly relates to what the subject is looking at. "Some people hear what they see: Car indicator lights, flashing neon shop signs, and people's movements as they walk may all trigger an auditory sensation," they write in the study.

Images packed with meaning, like two cars colliding, are more likely to trigger the auditory illusion. But even more abstract images can produce the effect if they have high levels of something called "motion energy." Motion energy is what you see in the video above when the structure bounces and the camera shakes. It's why a video of a race car driving straight down a road might have less of an auditory impact than a clip of a flickering abstract pattern.

The researchers categorize vEAR as a type of synesthesia, a brain condition in which people's senses are combined. Those with synesthesia might "see" patterns when music plays or "taste" certain colors. Most synesthesia is rare, affecting just 4 percent of the population, but this new study suggests that "hearing motion synesthesia" is much more prevalent.

[h/t BPS Research Digest]

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