If the prospect of an ever-expanding universe that eventually stretches into a vast emptiness isn’t depressing enough, there’s this: the universe may have cracks in it. Cracks, called cosmic strings, ...

Paul M. Sutter is an astrophysicist at The Ohio State University, host of Ask a Spaceman and "Space Radio," and author of "Your Place in the Universe." Sutter contributed this article to Space.com's ...