Is Earth FLAT or ROUND? Neil deGrasse Tyson, Bill Nye The Science Guy, and NASA's Michelle Thaller present the evidence to end this conspiracy theory once and for all. | Big Think

132K views · 2.6K reactions | How do we know Earth isn’t flat? For thousands of years people have known Earth is round. Ancient civilizations used the stars and shadows to figure it out. Mariners confirmed it by sailing around the globe. And when the space age began, we saw it with our own eyes — Earth is round! A NASA scientist explains how we’ve known for centuries that our planet is a sphere. Explore more: https://go.nasa.gov/4kITBXo | NASA Earth | Facebook