Carl Sagan once easily debunked flat Earthers with just a piece of cardboard
The science doesn't lie.

Carl Sagan on 'Cosmos'
Over the past few years, there has been a growing number of people who believe the Earth is flat. A 2019 YouGov survey of more than 8,000 Americans found that as many as one in six are "not entirely certain the world is round."
Flat Earth Theory has, surprisingly, gained a lot of traction. A 2021 study published in the National Library of Medicine posited that the theory is buoyed by "the cognitive tendency to interpret, favor, and recall information in order to strengthen one's personal beliefs" or, in other words, confirmation bias. Though the "how" and "why" of Flat Earth Theory and its popularity is fascinating (and troubling, to be honest), the scientifically proven truth is that the Earth is round. It is a globe. It is spherical.
Of course, the knowledge that the Earth is round is not new. Ancient Greek philosophers across centuries studied and found evidence that the Earth is indeed round thousands of years ago. Way back in the 6th century BC, Pythagoras first proposed the Earth was round from observing the shape of the Moon. In the 5th century, Empedocles and Anaxagoras noticed evidence of the Earth's true shape by observing its curved shadow during lunar eclipses. In the 4th century, Aristotle argued the Earth was round after noting how ships disappear "hull-first" over the horizon line. In the 3rd century, Eratosthenes actually calculated the Earth's circumference using geometry and shadows with shocking accuracy.

Naysayers remain skeptical, and there's probably no changing their minds, but to this day, experts insist the Earth is round and back it up with cold, hard science. NASA posted this video just days ago. Watch:
- YouTubewww.youtube.com
Here's where Carl Sagan comes in.
Sagan hosted the original version of TV's Cosmos: A Personal Journey in 1980-81. According to PBS, Cosmos would become "one of the highest-rated programs in the history of public television" largely due to Sagan's ability for "reinterpreting intricate scientific jargon into elegant and memorable statements that the common person can easily conceptualize and appreciate." The show would be revived in 2014 with astrophysicist Neil deGrasse Tyson at the helm.
In the first episode of Cosmos, Sagan easily proved the Earth was a sphere using a piece of cardboard, some sticks, and the work of none other than the ancient Libyan-Greek scholar, Eratosthenes. Watch:
- YouTubewww.youtube.com
"How could it be, that at the same moment, a stick in Syene would cast no shadow and a stick in Alexandria, 800 km to the north, would cast a very definite shadow?" Sagan asked. "The only answer was that the surface of the Earth is curved," he concluded. "Not only that, but the greater the curvature, the bigger the difference in the length of the shadows."
Considering the distance between the two cities and the lengths of the shadows they produced, Eratosthenes was able to determine that the Earth had a seven-degree curve. He used that calculation to speculate the Earth was 25,000 miles in circumference.
These days, we know that the earth is 24,901 miles in circumference, which means Eratosthenes was less than 100 miles off. Didn't we say his accuracy was shocking? Not bad for over 2,000 years ago.
This article originally appeared five years ago.



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An Irish woman went to the doctor for a routine eye exam. She left with bright neon green eyes.
It's not easy seeing green.
Did she get superpowers?
Going to the eye doctor can be a hassle and a pain. It's not just the routine issues and inconveniences that come along when making a doctor appointment, but sometimes the various devices being used to check your eyes' health feel invasive and uncomfortable. But at least at the end of the appointment, most of us don't look like we're turning into The Incredible Hulk. That wasn't the case for one Irish woman.
Photographer Margerita B. Wargola was just going in for a routine eye exam at the hospital but ended up leaving with her eyes a shocking, bright neon green.
At the doctor's office, the nurse practitioner was prepping Wargola for a test with a machine that Wargola had experienced before. Before the test started, Wargola presumed the nurse had dropped some saline into her eyes, as they were feeling dry. After she blinked, everything went yellow.
Wargola and the nurse initially panicked. Neither knew what was going on as Wargola suddenly had yellow vision and radioactive-looking green eyes. After the initial shock, both realized the issue: the nurse forgot to ask Wargola to remove her contact lenses before putting contrast drops in her eyes for the exam. Wargola and the nurse quickly removed the lenses from her eyes and washed them thoroughly with saline. Fortunately, Wargola's eyes were unharmed. Unfortunately, her contacts were permanently stained and she didn't bring a spare pair.
- YouTube youtube.com
Since she has poor vision, Wargola was forced to drive herself home after the eye exam wearing the neon-green contact lenses that make her look like a member of the Green Lantern Corps. She couldn't help but laugh at her predicament and recorded a video explaining it all on social media. Since then, her video has sparked a couple Reddit threads and collected a bunch of comments on Instagram:
“But the REAL question is: do you now have X-Ray vision?”
“You can just say you're a superhero.”
“I would make a few stops on the way home just to freak some people out!”
“I would have lived it up! Grab a coffee, do grocery shopping, walk around a shopping center.”
“This one would pair well with that girl who ate something with turmeric with her invisalign on and walked around Paris smiling at people with seemingly BRIGHT YELLOW TEETH.”
“I would save those for fancy special occasions! WOW!”
“Every time I'd stop I'd turn slowly and stare at the person in the car next to me.”
“Keep them. Tell people what to do. They’ll do your bidding.”
In a follow-up Instagram video, Wargola showed her followers that she was safe at home with normal eyes, showing that the damaged contact lenses were so stained that they turned the saline solution in her contacts case into a bright Gatorade yellow. She wasn't mad at the nurse and, in fact, plans on keeping the lenses to wear on St. Patrick's Day or some other special occasion.
While no harm was done and a good laugh was had, it's still best for doctors, nurses, and patients alike to double-check and ask or tell if contact lenses are being worn before each eye test. If not, there might be more than ultra-green eyes to worry about.