Are there flat-Earthers in Connecticut? Sure — they're around.

An astronomical society Facebook post about a lecture series devolved into an argument over the shape of the Earth.

“We had a flat-Earther respond to one of our Facebook posts last week,” said Westport Astronomical Society president Shannon Calvert. “It did not go well for him.”

The society was simply trying to promote a lecture by Yale Physicist Meg Urry called “Black Holes and the Galaxies They Grow In.”

Instead, Facebook user Marcos Obed Echevarria decided to start a debate on basic science.

“Everything is just a theory from black holes to the roundness of the Earth,” he wrote. “Stop lying.”

Echevarria said “observable experiments” proving the existence of black holes and the round Earth don’t exist. “You won't find any ... you just overreacting.”

Calvert attempted to be a voice of reason. Addressing Echavarria directly he wrote, “Scientific theories describe processes, not objects. Black holes and the shape of the Earth are not theories, but specific facts confirmed by observation and experiment.”

“Notably, the black hole at the center of our own galaxy was confirmed last fall by direct observations of a star whipping around the event horizon, and pretty much everyone in North America could directly observe the shape of the Earth as its shadow crossed the moon late last month,” he wrote.

Echevarria wasn’t having any of it. He agreed that black holes are observable, but only “by cgi and compositions”

As for the roundness of the Earth, he argued that the straightness of the horizon is proof that the planet is flat.

“A curve ball doesn't have a line you understand? You can do any experiments related to the curve and trust me you won't find anything sir and by the way water doesn't blend,” he wrote. “You can do any observable experiment if you want to.”

Calvert responded, “Yes, the curve of a ball will appear to be a straight line if the ball is large enough. Look closely at a marble and you'll see that it's a very tight curve. Look closely at a large beach ball and you'll see that it's a much more gentle, shallow curve. If that beach ball was 7,900 miles in diameter, the curve would be so shallow that it would look like a perfectly straight line.”

So-called “flat-Earthers” are not so few and far-between. In 2017, the first-ever Flat Earth International Conference drew 500 attendees.

A documentary now on Netflix called “Behind the Curve” follows the best known advocates of the Flat Earth movement, primarily YouTuber Mark Sargent.

Last year, a local meetup was held in Uncasville, though the total number of attendees was not immediately available.

“Remember that nearly half the people on Earth have below average intelligence,” Calvert said.