Carl Sagan explained the thought process of the ancient Greek scientist Eratosthenes, who determined the circumference of the ...

In most Ancient Greek philosophical circles, the theory of a spherical earth was accepted by around the 5th century BC, and ...

Dedicated cyclists set different goals to strive for, from cycling 40 miles in a day to cycling 5,000km or around 3106 miles in a year. I love cycling because it’s fun working your legs, hips, and ...

“The cosmos is also within us, we're made of star-stuff. We are a way for the cosmos to know itself.” - Carl Sagan Compared to the Sun, how big is the Earth? What is a scale model and how does it help ...

Lines of latitude are imaginary horizontal lines that circle the Earth, helping measure how far north or south a location is ...