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Neil deGrasse Tyson Proves Earth Is a Sphere, Because Apparently There are Still People Who Don’t Believe That?

"We have video. From space. Of the rotating, spherical Earth. The earth is round."

One would think that ideas like “the Earth is round” wouldn’t be controversial at this point. After all, we’ve been to space and seen stuff. So, you know, whatever. But apparently there are enough people for whom “the Earth is round” is not a statement of fact that astrophysicist and Professional Explainer of Science to Average People, Neil deGrasse Tyson, felt the need to address this on his show, Star Talk.

Joined by comedian Chuck Nice, Tyson at first gave a very simple response to flat-Earthers: “We have video. From space. Of the rotating, spherical Earth. The earth is round.” Which, you know, yeah. But while they jokingly started to “wrap up” their conversation, they end up creating a nine-minute video talking about the many pieces of evidence that prove the Earth is round. What’s more, that it didn’t take modern scientific advancements and photographic evidence for people to know this. People have reasoned that the Earth must be a sphere since the time of the ancient Greeks.

Tyson describes an experiment performed by the Greek Eratosthenes, who lived in Alexandria around 250 B.C. Eratosthenes noticed that in the Egyptian city of Syene (near modern-day Aswan), you could see all the way to the bottom of a well at noon during the summer solstice. Yet on the same day, you couldn’t see to the bottom of a well in Alexandria.

A scene from Neil deGrasse Tyson's "Star Talk" on the Earth being a sphere

He also talks about the simple fact that during a lunar eclipse, the shadow of the Earth against the moon is always curved. If the Earth were flat, the shadow would look very different. Oh yeah, and then there’s the thing that anyone who’s spent any time on boats knows: when a boat sails off toward the horizon, it looks like it’s descending, fading from view from bottom to top. That wouldn’t happen if the boat were just sailing off into endless flatness.

Now, I know that most of you reading this know all this, but it’s astounding to think that there are still non-children to whom this needs to be explained. Tyson says:

“For me, the fact that there’s a rise of flat-Earthers is evidence of two things: One, we live in a country that protects free speech. And two, we live in a country with a failed educational system. Our system needs to train you, not only in what to know, but how to think about information and knowledge and evidence. If you don’t have that kind of training, you’d run around and believe anything.”

The video closes out with a mention of an awesome-looking site called, where you can sign up for free and learn more about science and math concepts in a fun and playful way. Because the only way to combat ignorance is with knowledge and an endless curiosity.

(via, image: screencap)

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Teresa Jusino (she/her) is a native New Yorker and a proud Puerto Rican, Jewish, bisexual woman with ADHD. She's been writing professionally since 2010 and was a former TMS assistant editor from 2015-18. Now, she's back as a contributing writer. When not writing about pop culture, she's writing screenplays and is the creator of your future favorite genre show. Teresa lives in L.A. with her brilliant wife. Her other great loves include: Star Trek, The Last of Us, anything by Brian K. Vaughan, and her Level 5 android Paladin named Lal.