/What Earth would look like if we drained all the oceans (video) – Treehugger

What Earth would look like if we drained all the oceans (video) – Treehugger

A NASA scientist shows us the three-fifths of the planet’s surface that we don’t get to see.

These days the concern may be more about what Earth would look like if all the ice melted – but this look at what we’d see if all the oceans drained away is seriously fascinating.

Now of course, all the oceans can’t exactly drain away – where would they go? We have a specific amount of water on the planet, it just moves around in different phases to different places. But it used to be that there was less water in the oceans, back when it was locked up in ice on the land.

In 2008, NASA physicist and animator Horace Mitchell created a video showing what the planet would look like if all the oceans slinked away. More recently, former NASA planetary scientist James O’Donoghue gave the video an update. He tweaked the speed a bit and added depth tracking to show levels.

“I slowed down the start since, rather surprisingly, there’s a lot of undersea landscape instantly revealed in the first tens of meters,” O’Donoghue told Business Insider.

As the water drains, more features are revealed, including the land bridges that provided humans a way to reach other continents. “When the last ice age occurred, a lot of ocean water was locked up as ice at the poles of the planet. That’s why land bridges used to exist,” O’Donoghue said. “Each of these links enabled humans to migrate, and when the ice age ended, the water sort of sealed them in.”

On YouTube, O’Donoghue eplains:

“This animation simulates a drop in sea level that gradually reveals this detail. As the sea level drops, the continental shelves appear immediately. They are mostly visible by a depth of 140 meters, except for the Arctic and Antarctic regions, where the shelves are deeper. The mid-ocean ridges start to appear at a depth of 2000 to 3000 meters.”

The mid-ocean ridge is wild; it is the most extensive chain of mountains on the planet, winding along for nearly 65,000 kilometers (40,390 miles). Most of it (90 percent) is underwater. Look for this pattern to begin emerging at around 2,000 meters:

mid-ocean ridgeThe nearly continuous, global mid-ocean ridge system snakes across the Earth’s surface like the seams on a baseball. (NOAA)/Public Domain

Another thing that’s hard to miss is once we hit around 6,000 meters. Most of the ocean floor is now visible, but it takes another 5,000 meters to be fully empty. Eagle eyes will notice that the Marianas Trench, the deepest spot on the planet, is slowly draining during this time. With the screen expanded, watch the crescent shape line that’s roughly between Australia and Japan.

I must have watched this at least 10 times in a row, with screen expanded (which I really recommend) – and I kept starting and stopping it to take in the details. I couldn’t help but marvel at the ocean floor and imagine what it must have been like to be able to walk from Siberia to Alaska or from mainland Europe to Great Britain.

“I like how this animation reveals that the ocean floor is just as variable and interesting in its geology as the continents,” O’Donoghue said. Adding that emptying the seas unearths “not only the ocean bottom, but also the ancient story of humanity.”

Via Business Insider

A NASA scientist shows us the three-fifths of the planet’s surface that we don’t get to see.