Every Day Is Special: August 30 – Longest Canyon in the World?

August 30 – Longest Canyon in the World?

Posted on August 30, 2017

The Grand Canyon in Arizona is one of the world's largest canyons and is probably the most famous.

There are, however, deeper canyons and longer canyons, including Tibet's Yarlung Tsangpo Grand Canyon.

Note: the words largest, longest, and deepest can be imprecise when speaking of canyons, given the variations of measurement from rim or from nearby mountaintops, given the fact that we could be talking about the total area of the canyon system, given the fact that canyons tend to have lots of branches. Another problem with assigning "longest" or "deepest" awards is that many canyons in the Himalaya Mountains are pretty much inaccessible - so there may be some record breakers there that we just don't know about.

Speaking of inaccessible, today we commemorate a canyon discovered on this date in 2013. It is about 800 km (almost 500 miles) long and about 800 m (about 2,600 feet) deep in some places. Why would a canyon this huge take so long for humans to discover it?

This canyon, which was carved out by a river over four million years ago, is in Greenland and is covered by the ice sheet covering that huge island.

If it's covered by ice...you may wonder how we know about Greenland's Grand Canyon. Scientists used ice-penetrating radar to detect it. The bottom of the canyon is V-shaped, not U-shaped; that indicates that it was carved by running water, not flowing ice.

If the scientists' measurements are correct, it is the new record-breaker in length, although both Arizona's Grand Canyon and Tibet's Grand Canyon are deeper.

Check out this NASA animation of the canyon.