Fact check: Oceans have topographic features and are held to Earth by gravity

Kate S. Petersen, USA TODAY
·4 min read
147

The claim: Earth's oceans have no 'elevation features' and are in a 'container'

A Facebook post shows an image of a string of islands in a calm expanse of ocean alongside a diagram of different topographic features found on the ocean floor.

"The ocean has no elevation features to its surface hence why we have SEA-LEVEL," reads part of the caption in the April 20 post (direct link, archive link). "The only way to establish a level is to contain the water from all sides first. Every huge body of water needs to be contained from all sides."

The caption goes on to claim that this container is Antarctica, which forms a 360-degree circle around the Earth.

The post was shared more than 80 times in a day.

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Our rating: False

The oceans have topographic features and are held onto Earth by gravity. Antarctica is a continent in the southern hemisphere completely surrounded by oceans.

Earth's oceanshave topographic features

Despite the post's claim, oceans have topography in the same way as land, according to NASA.

"Earth’s seas and oceans have high and low points, just like Earth’s continents have hills and valleys," reads the agency's website."The difference is that sea surface topography is affected by temperature, currents and underwater mountains and trenches."

For instance, undersea mountains have a gravitational pull that distorts the surface of the water. The effect is so predictable that researchers use ocean surface topography to map the ocean floor, according to Science magazine.

Researchers study ocean surface topography using satellite-based radar, according to the National Oceanic and Atmospheric Administration.

"Satellite altimeters use active radar to observe the surface height of the ocean which is not smooth or flat," reads the agency's website.

Fact check roundup: Debunking the flawed science behind flat Earth claims

The post claims Antarctica forms a 360-degree circle around Earth, echoing a claim previously debunked by USA TODAY that Antarctica is a wall circling the planet. The continent of Antarctica is surrounded by oceans, visible in satellite images and regularly visited by tourists.

Bethan Davies, a glacial geologist at Newcastle University, previously told USA TODAY that such a wall isn't physically possible.

Antarctica is "fringed by floating ice shelves, which have previously been mistaken by flat earth theorists as these ice walls," she said. "Ice shelves have to be attached to the mainland. ... A circular ice wall would be unstable and due to lack of inflowing glacier ice would rapidly thin and disintegrate."

Rather than being contained by such a wall, the oceans are held in place by gravity, Jason Steffan, a mathematician and physicist at the University of Nevada, previously told USA TODAY.

"Gravity is the force that pulls all objects in the universe toward each other," reads the NOAA website. "On Earth, gravity pulls all objects 'downward' toward the center of the planet."

The claims were posted on a page that often produces content associated with flat Earth theory, the erroneous idea that the Earth is flat.

USA TODAY reached out to the Facebook user who shared the post for comment.

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This article originally appeared on USA TODAY: Fact check: Earth oceans have topography, aren't contained by ice wall