Protecting the U.S. would require novel solutions, like orbiting missile interceptors that can destroy incoming attacks.

Burrowing under soil opens up a whole new world, especially when that soil is on other planets. Getting under the top layer ...

The Pliocene epoch, which lasted from 5.3 million to 2.6 million years ago, was a consequential time in Earth's history. The Isthmus of Panama formed, connecting North and South America, and the ...