The 2 March 2020 article was shared on Facebook in South Africa, and flagged as potentially false. We investigated.
Under the sea?
“Nasa physicist and animator Horace Mitchell made a video in 2008 showing what our planet would look like if the oceans were all drained, and this video was given an update recently by Nasa planetary scientist James O’Donoghue,” the article reads.
It links to an interview with O’Donoghue on the US news site Business Insider.
The scientist no longer works at the US National Aeronautics and Space Administration, or Nasa, but O’Donoghue has recently updated the video, first published by Nasa in 2008.
The original video was animated by Horace Mitchell by combining satellite images of the visible surface of the Earth with data on the depth of the ocean floor.
The visible parts of the Earth were recorded by Nasa’s Blue Marble: Next Generation programme, which snapped high resolution colour images of Earth’s surface in each month of 2004. The images can be viewed in Nasa’s Visible Earth catalogue.
Images based on numerous data sources
Some of the data on ocean depth is from a 2006 survey by the US National Oceanic and Atmospheric Administration, NOAA. The survey compiled recorded values of the height above or depth below sea level in a fine grid of points across the Earth’s surface.
The rest of the ocean floor data was gathered in the 2008 International Bathymetric Chart of the Arctic Ocean and the Smith and Sandwell global topographic and bathymetric survey.
Topography studies the shape and features of land surfaces. Bathymetry studies the shape and features of surfaces under oceans, seas and rivers. This data is gathered in different ways. Some surveys use laser light or radar to measure the height of geographic formations, while some even detect tiny changes in Earth’s gravitational field.
Nasa scientists won’t stop imagining the Earth without oceans
In 2008, Nasa released the first version of the animation, showing the Earth’s oceans slowly draining away to reveal a topographic map of the seafloor beneath them.
O’Donoghue, who currently works for the Japan Aerospace Exploration Agency, posted his own version of the animation on YouTube on 12 December 2019.
The new video slows down some parts of the original animation, and has a higher resolution than the 2008 video. He created it using the same data sources as Mitchell.
But the two aren’t the only Nasa scientists to imagine Earth’s oceans draining away.
In 2006 Randall Munroe left his job as a programmer and roboticist at Nasa to work on his popular webcomic xkcd. In 2012, Munroe started the blog What If, where he answered often absurd hypothetical questions from readers using scientific methods and real-world data.
In July 2013, Munroe put his unique combination of science and humour into answering a question about draining the Earth’s water. He also worked out what could happen if the drained water was moved to Mars. – Keegan Leech
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