Like stretch marks left on skin that expanded too quickly or cracks embedded in freezing ice, cosmic strings are artifacts of ...

In the season 2 episode "Mirror, Mirror," Star Trek perfected the alternate universe trope long before Hollywood's multiverse obsession.

Time travel has long been a topic of science fiction, filled with thrilling possibilities and mind-bending problems. The most famous of these problems is the "grandfather paradox". If someone travels ...

James is a published author with multiple pop-history and science books to his name. He specializes in history, space, strange science, and anything out of the ordinary.View full profile James is a ...

Can we journey through time? Sci-fi author Dete Meserve presents a compelling case for our future in the past. When you purchase through links on our site, we may earn an affiliate commission. Here’s ...

This month marks 40 years since Michael J. Fox, as Marty McFly, jumped into a souped-up DeLorean and went back in time, putting his very future existence at risk. (SOUNDBITE OF FILM, "BACK TO THE ...

There’s little more satisfying than a solid sci-fi series, except perhaps a sci-fi series that brilliantly explores the concept of time travel. Any sci-fi fan can tell you that not all time travel ...

Time travel is one of the hallmarks of science fiction, but many time-travel-based movies have plots that leave one with a headache just thinking about them. What if you could travel into the past, ...