Einstein's 1917 paper, "Cosmological Considerations in the General Theory of Relativity," applied general relativity to the universe as a whole, establishing a firmer basis for cosmology. To create a ...

In our mind’s eye, the universe seems to go on forever. But using geometry we can explore a variety of three-dimensional shapes that offer alternatives to “ordinary” infinite space. When you gaze out ...

A road bike frame is essentially three big tubes stuck together in a triangle, four thinner ones to support the rear wheel and a fork to hold the front wheel and allow it to turn. But it’s a lot more ...