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Human Noise Reaches to the Deepest Part of the Ocean

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If a ship passes over the deepest part of the ocean but there’s nobody there to hear it, does it still make a sound? It sure does. New audio recordings from the Mariana Trench, the deepest part of the world's oceans, have captured the sounds of whales, distant earthquakes, storms, and even ships passing tens of thousands of feet above.

Challenger Deep is a valley inside the trench, seven miles below the surface of the ocean. To give you some idea of just how deep that is: If you chiseled Mount Everest off its foundation and dropped it into the Challenger Deep, the mountain’s peak would still be a mile underwater.

Image credit: Center for Coastal and Ocean Mapping - Joint Hydrographic Center

The valley is of great scientific interest, but its distance from the surface and the tremendous amounts of pressure down there have made it hard to study. A team of engineers created a special titanium-coated hydrophone, or underwater microphone, but even they weren’t sure it would work.

"We had never put a hydrophone deeper than a mile or so below the surface, so putting an instrument down some seven miles into the ocean was daunting," engineer Haru Matsumoto said in a press release. "We had to drop the hydrophone mooring down through the water column at no more than about five meters per second. Structures don't like rapid change, and we were afraid we would crack the ceramic housing outside the hydrophone." 

Researchers dropped the hydrophone over the side of a ship. More than six hours passed before the equipment reached the valley floor, but once it did, it began recording. When the research team collected the hydrophone, they brought up 23 days' worth of noise from the bottom.

"You would think that the deepest part of the ocean would be one of the quietest places on Earth," chief project scientist Robert Dziak said in the press release. "Yet there really is almost constant noise from both natural and man-made sources. The ambient sound field at Challenger Deep is dominated by the sound of earthquakes, both near and far was well as the distinct moans of baleen whales and the overwhelming clamor of a category 4 typhoon that just happened to pass overhead. There was also a lot of noise from ship traffic, identifiable by the clear sound pattern the ship propellers make when they pass by."

Curious what those “distinct moans” and that “overwhelming clamor” sound like? Listen for yourself:

The Challenger Deep soundtrack is impressive on its own, as both scientific data and a demonstration of human ingenuity. But it’s also an indicator that our effects on the environment reach farther than we could have imagined. Scientists now know that anthropogenic (human-created) sound wreaks havoc on marine ecosystems, from the largest whales to the smallest fish eggs on coral reefs. From city streets to the Challenger Deep, our noise is more than just noise.

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The Most (and Least) Expensive States for Staying Warm This Winter
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It’s that time of year again: Temperatures outside have plummeted, while your monthly heating bill is on the rise. If you want an idea of how much heat will cost you this winter (perhaps you blocked out last year’s damage to your bank account), one reliable indicator is location.

Average energy expenses vary from state to state due to factors like weather, house size, and local gas prices. Using data from sources including the U.S. Energy Information Administration and the Environmental Protection Agency, WalletHub calculated the average monthly utility bill totals for all 50 states plus Washington D.C. in 2017.

Source: WalletHub

The personal finance website looked at four energy costs: electricity, natural gas, car fuel, and home heating oil. After putting these components together, Connecticut was found to be the state with the highest energy costs in 2017, with an average of $380 in monthly bills, followed by Alaska with $332 and Rhode Island with $329.

That includes data from the summer and winter months. For a better picture of which state’s residents spend the most on heat, we have to look at the individual energy costs. Michigan, which ranks 33rd overall, outdoes every other state in the natural gas department with an average bill of $60 a month. Alaska is close behind with $59, followed by Rhode Island With $58.

People living in Maine prefer oil to heat their homes, spending $84 a month on the fuel source. All six New England states—Maine, Connecticut, Rhode Island, Vermont, New Hampshire, and Massachusetts—occupy the top six spots in this category.

So which state should you move to if you want to see your heating bill disappear? In Florida, the average household spends just $3 a month on natural gas and $0 on heating oil. In Hawaii, on average, the oil bill is $0 as well, and slightly higher for gas at $4. Of course, they make up for it when it comes time to crank up the AC: Both states break the top 10 in highest electricity costs.


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Why Are Glaciers Blue?
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The bright azure blue sported by many glaciers is one of nature's most stunning hues. But how does it happen, when the snow we see is usually white? As Joe Hanson of It's Okay to Be Smart explains in the video below, the snow and ice we see mostly looks white, cloudy, or clear because all of the visible light striking its surface is reflected back to us. But glaciers have a totally different structure—their many layers of tightly compressed snow means light has to travel much further, and is scattered many times throughout the depths. As the light bounces around, the light at the red and yellow end of the spectrum gets absorbed thanks to the vibrations of the water molecules inside the ice, leaving only blue and green light behind. For the details of exactly why that happens, check out Hanson's trip to Alaska's beautiful (and endangered) Mendenhall Glacier below.

[h/t The Kid Should See This]

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