Having read the recent post here on where Earth’s water came from, I just stumbled across an interesting article over at ExtremeTech.com from June of this year, evidently commenting on a find that was originally reported in Science (at least, that’s what I’ve gathered from reading a bit about it elsewhere). I’m not sure if anything came of this or if it was mentioned here and I missed it (I couldn’t find it in a search), but I thought it might spark some interesting discussion.
From the article, titled Scientists discover an ocean 400 miles beneath our feet that could fill our oceans three times over:
After decades of theorizing and searching, scientists are reporting that they’ve finally found a massive reservoir of water in the Earth’s mantle — a reservoir so vast that could fill the Earth’s oceans three times over. This discovery suggests that Earth’s surface water actually came from within, as part of a “whole-Earth water cycle,” rather than the prevailing theory of icy comets striking Earth billions of years ago.
This new study, authored by a range of geophysicists and scientists from across the US, leverages data from the USArray — an array of hundreds of seismographs located throughout the US that are constantly listening to movements in the Earth’s mantle and core. After listening for a few years, and carrying out lots of complex calculations, the researchers believe that they’ve found a huge reserve of water that’s located in the transition zone between the upper and lower mantle — a region that occupies between 400 and 660 kilometers (250-410 miles) below our feet.
Finally, here’s a fun thought that should remind us that Earth’s perfect composition and climate is, if you look very closely, rather miraculous. One of the researchers, talking to New Scientist, said that if the water wasn’t stored underground, “it would be on the surface of the Earth, and mountaintops would be the only land poking out.” Maybe if the formation of Earth had be a little different, or if we were marginally closer to the Sun, or if a random asteroid didn’t land here billions of years ago… you probably wouldn’t be sitting here surfing the web.