The claim: Image of Chicago skyline taken in Indiana proves Earth is flat
Social media is flooded with posts that claim to prove the Earth is flat. A recent example is a post that claims a photo of Chicago taken from Indiana demonstrates the Earth's flatness.
"If the earth was really a globe, the Chicago skyline from Indiana would be hidden by 1,473 ft. of Earth Curve," reads the text included in one such Nov. 6 Instagram post (direct link, archive link). The post, which garnered more than 2,000 likes in one week, includes an image of the Chicago skyline taken from across Lake Michigan at the Indiana Dunes State Park.
But the claim is false.
Scientists say the photo actually proves that the Earth is indeed curved. While the buildings in the Chicago skyline are visible in the photo, parts of the buildings are obscured by the curve in the Earth. A simple trigonometric equation confirms that the buildings of the Chicago skyline are indeed visible from the Indiana Dunes State Park, where the image was taken.
USA TODAY reached out to the user who shared the post for comment.
Photo of skyscrapers demonstrates Earth is round, not flat
The photo used in the meme matches an image captured by a photographer in 2019. That image was taken at the Indiana Dunes State Park, located just across the Indiana-Illinois border on the shores of Lake Michigan.
But the image doesn't prove the Earth is flat like the post claims, according to Rona Oran, a researcher in the Massachusetts Institute of Technology's Department of Earth, Atmospheric and Planetary Sciences.
It proves the opposite.
"The image actually demonstrates that the Earth is round," Oran said. "(The bottom) parts of the buildings are actually obscured because the Earth is curved."
Oran noted the lower halves of the buildings are not visible in the photo. According to Oran's calculations, roughly 500 feet of the bottom of the Willis Tower, the tallest building in Chicago, would not be visible based on the distance the picture was taken from.
Jason Steffen, an associate professor of physics at the University of Nevada Las Vegas, said the viral claim's math is wrong.
"The claim that there is 1,400 feet of elevation that is in the way is not correct," Steffen said to USA TODAY in an email. "When I do the calculation, I get ~500 feet. So, any building taller than 500 feet should be visible."
Steffen explained his calculation took into account variables such as the height of the Willis Tower, elevation and the distance between Chicago and Dunes State Park. He concluded it is possible to see the city's skyline from the park despite the curve of the Earth.
Peter Littlewood, the chair of the department of physics at the University of Chicago, said the formula for determining whether a structure would be visible from a certain area is "high-school trigonometry."
"It's pretty clear that you can see the Chicago skyline from the dunes," said Littlewood in an email to USA TODAY.
Humans have known the Earth is round for more than 2,000 years. The ancient Greeks measured shadows during summer solstices and also calculated Earth's circumference. Since then, scientists have only discovered more evidence to prove this is true - including seeing Earth itself from space.
Fact Check: Ample evidence the Earth is round and rotating, contrary to persistent social media claims
Our rating: False
Based on our research, we rate FALSE the claim that an image of Chicago's skyline taken in Indiana proves the Earth is flat. Scientists say the post's calculations are incorrect and the photo actually proves the opposite. The Chicago skyline is visible from the photo's location at the Indiana Dunes State Park, but the curve of the earth means the bottom of the buildings is obscured.
Our fact-check sources:
Rona Oran, Nov. 15, Phone interview with USA TODAY
Jason Steffen, Nov. 11, Email exchange with USA TODAY
Peter Littlewood, Nov. 10 , Email exchange with USA TODAY
Linda Myszkowski, July 27, 2019, Instagram post
Mark Brennan, Oct. 26, 2008, Chicago Skyline View from Adler Planeterium
Joshua Mellin, Aug. 22, 2018, Chicago Skyline Sunset: Southside | Sears Tower (Willis Tower)
Willis Tower, accessed Nov. 15, History and Facts
American Physical Society, accessed Nov. 18, This Month in Physics History
USA TODAY, Nov. 17, Ample evidence the Earth is round and rotating, contrary to persistent social media claims
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This article originally appeared on USA TODAY: Fact check: Image of Chicago skyline proves earth is round, not flat