We all have heard about flat-Earthers, the growing group of conspiracy theorists who believe that our Earth is a flat, pancake-shaped space object rather than a perfect sphere.

The proponents of this theory, including rapper B.o.B and NBA star Kyrie Irving, posit that the entire set of images captured from space is falsified. One of the members of the group, ‘Mad’ Mike Hughes, even plans a rocket ride to capture photographic evidence to see for himself.

But, all of that is way too much effort for astrophysicist Neil DeGrasse Tyson. In the latest clip of his ‘Star-Talk’ show, Tyson took a simple, easy-to-understand approach to debunk all the misconceptions about the actual shape of our planet.

Speaking to stand-up comedian Chuck Nice, Tyson gave several facts to prove how even the ancient Greeks knew that we are living in a spherical world.

"What's odd is there are people who think that Earth is flat but recognize that the moon is round. Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune and the sun are all spheres,” he said in the video.

Tyson then goes on to add about a lunar eclipse during which the Earth casts a direct shadow over the moon. According to him, if the Earth were really flat, the celestial line-up would have resulted in a straight-edged shadow rather than a curved one, which only forms from a sphere and has been observed several times in the past.

Among other things, the astrophysicist also cited sophisticated experiments and the example of a ship sailing toward the horizon and then disappearing to explain that the Earth is indeed a sphere. He said if Nice started walking toward the east and continue in that direction, he would eventually come back to the same place.

At the end of the nine-minute-long clip, Tyson expressed his own views toward the proponents of the flat-Earth theory. He said the rise of this specific group suggests that we live in a country where free speech is protected and the education system is failing. 

"Our system needs to train you not only what to know, but how to think about information, knowledge, and evidence. If you don't have that kind of training, you'd run around and believe anything."