Time travel has shifted from pure fantasy to a serious, if highly constrained, topic in modern physics. The equations that describe gravity, quantum fields and the structure of spacetime now allow ...

The Party No One AttendedOn June 28, 2009, physicist Stephen Hawking held a small party at the University of Cambridge. He ...

The ability to jump forward and backwards in time has long fascinated science fiction writers and physicists alike. So is it really possible to travel into the past and the future? Doctor Who is ...

Cosmic strings are artifacts of what the universe looked like in the moments before it rapidly changed from a high-energy to low-energy environment—the Big Bang. Today, scientists believe cosmic ...

These theoretical particles ignore the basic structure of cause and effect. If scientists ever prove they’re real, tachyons would shatter our understanding of reality. But relativity also tells us ...

The American astrophysicist explains how relativity allows us to experience the passage of time at different rates, and why ...

Moskowitz: We’re going to have a little friendly debate. Billings: Really? I came for a throwdown. Moskowitz: Well, a wrangle. A parley. A confab. Lee, what do you have against time travel? Billings: ...

The theoretical physics and paradoxes of time travel often brush up against multiverse theory and the idea of alternate universes. While many sci-fi writers have wondered if time travel into the past ...

Most time travel movies don’t sweat the math — or, more accurately, the quantum physics of how time travel might actually work. The writers and directors include the time-travel concepts that will ...

If you want to attend Stephen Hawking's time travel party, you better figure out how time travel works for a journey back to 2009. Hey everyone, Stephen Hawking is throwing a party, and we're all ...