Now here's some ice you wouldn't want to fall through. A team of British scientists working in Antarctica have uncovered a massive trench hidden beneath several miles of ice and snow. The valley is two miles deep, 186 miles long and, in some places, 15 miles wide. That's deeper than the Grand Canyon and almost as long. At some spots, the trench descends more than 6,500 feet below sea level.

The valley was apparently carved out by moving ice fields millions of years ago and has remained hidden from sight — under several miles of ice — to all who explored the region until now.

The trench, which has been dubbed the Ellsworth Trough after the surrounding Ellsworth mountain range, was discovered by researchers from Newcastle University, the University of Bristol's Glaciology Center, the British Antarctic Survey and the universities of Edinburgh, Exeter and York. Their research was published in September 2013 in the Geological Society of America Bulletin, but is only being broadly publicized now.

In a news release from Newcastle University, lead author Neil Ross describes the discovery of the valley as "serendipitous." They had some data on each end of the valley from ice-penetrating radar, but couldn't figure out what was between those two points. They turned to the sky for the answers, tapping satellite data to figure out the true scope of the valley, which Ross said "is so vase that it can be seen from space."

The discovery, Ross said, underscores the importance of continued exploration. "To me," he said, "this just goes to demonstrate how little we still know about the surface of our own planet. The discovery and exploration of hidden, previously unknown landscapes is still possible and incredibly exciting, even now."

According to the publication about the trench, the discovery illustrates when and how the West Antarctic ice sheet originated and grew, as well as provides clues into how the ice sheet changed its size and shape during previous warming periods in the Earth's climate. Another news release from Bristol University describes the importance of this information: "While the idea of West Antarctic Ice Sheet growth and decay over the past few million years has been discussed for decades, the precise location where the ice sheet may originate from in growth phases, and decay back to in periods of decay, has not been known," said professor Martin Siegert. "By looking at the topography beneath the ice sheet using a combination of ice-penetrating radio-echo sounding and satellite imagery, we have revealed a region which possesses classic glacial geomorphic landforms — such as u-shaped valleys and cirques — that could only have been formed by a small ice cap, similar to those seen at present in the Canadian and Russian High Arctic. The region uncovered is, therefore, the site of ice sheet genesis in West Antarctica."

According to the paper, the margins of the trench would represent the "pinning point" at which any future retreat of the West Antarctic ice sheet would stop.

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