How do we know the Earth isn’t flat? For thousands of years people have known the Earth is round. Ancient civilizations used the stars and shadows to figure it out. Mariners confirmed it by sailing around the globe. And when the space age began, we saw it with our own eyes — the Earth is round!
A NASA scientist explains how we’ve known for centuries that our planet is a sphere.
Explore more: https://www.nasa.gov/history/90-years-of-our-changing-views-of-earth/
Producers: Scott Bednar, Pedro Cota, Jessie Wilde
Editor: Pedro Cota
Credit: NASA
Download Video: https://images.nasa.gov/details/How%20Do%20We%20Know%20the%20Earth%20Isn't%20Flat
A NASA scientist explains how we’ve known for centuries that our planet is a sphere.
Explore more: https://www.nasa.gov/history/90-years-of-our-changing-views-of-earth/
Producers: Scott Bednar, Pedro Cota, Jessie Wilde
Editor: Pedro Cota
Credit: NASA
Download Video: https://images.nasa.gov/details/How%20Do%20We%20Know%20the%20Earth%20Isn't%20Flat
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NewsTranscript
00:00That's a great question.
00:07In fact, two or three thousand years ago, ancient people on this planet that did great
00:13things figured out that the earth was round, it was a sphere.
00:17This was a magical revelation for the Greeks and the Egyptians who were able to see from
00:22the motions of the stars and the way the sun moved, they saw the way the sun's shadow worked
00:28in different places.
00:30And they figured, well, it's only possible if the earth is round.
00:34And they took that information and it extended into the time of the great mariners that explored
00:39our earth by ships.
00:40They made the first orbit of earth by sea and they knew the earth was round, allowing
00:45them to go across one ocean and come back home the other way.
00:48If the earth were flat, they would have sailed off the end.
00:51And so we knew that.
00:52But then, at the dawn of the space age, in the late 50s and 60s, we were able to see
00:58for ourselves that our beautiful home is a gorgeous round object known as a sphere.
01:04And that was really special.
01:05It put ourselves into context of our solar system and our universe.
01:09We have a big round sun and a beautiful round earth and a round Mars.
01:13And today we use the roundness of earth, the spherical earth, to use methods in space geodesy
01:20to figure out where we are, where we're going.
01:23I haven't been lost in years.
01:25That's pretty good.
01:26What's happening to the earth?
01:27What's happening to our oceans as we take the pulse of our planet?
01:31And consider other worlds beyond as we explore those.
01:34So as we get ready to go back to the moon with women and men and explore other worlds,
01:39the roundness of our solar system and our universe is a special thing.
01:43And we should embrace that as we understand why our planet isn't flat.