This photo provided by NASA shows the southernmost point of South America and a bit of Antarctica, from the Juno spacecraft during a flyby of the Earth, Wednesday, Oct. 9, 2013.
(AP Photo/ NASA)
The Earth hums, and the scientists have for the first time recorded sound in the ocean. With the help of seismometers in the Indian Ocean, researchers picked up on the sound that is much, much too low for mere human ears to hear, reports Live Science.
No recording is available, but a scientist from the University of Columbia not involved in the study in Geophysical Research Letters shows National Geographic a rough description: “It’s like taking a piano and banging all the keys at the same time,” says Spahr Webb.
“Except that she doesn’t like harmonics. They are eccentric frequencies.” And ultra-low: to be Specific, the hum is between 2.9 and 4.5 millihertz, and the man can only start hearing things at about 20 hertz, or about 10,000 times higher.
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While scientists have long known about the hum, and a previously recorded on the land, in the new research can shed more light on the interior of the Earth, and maybe even help map of distant planets, reports the Washington Post.
The leading theory is that the hum is caused by the waves interacting with each other at the bottom of the ocean, which results in vibrations are sent down into the earth’s crust.
The process, however, is complex and not fully understood. For example, “sometimes a wave on a shallow shore somewhere ripples across the rough sea floor, and adds its own frequency to the hum,” per Post.
What is the exact reason, one thing is clear: the low drone is a constant. Read more speculation about the hum here.
This article originally appeared on Newser: Earth Hum Heard as Never before