"The singularity is the most mysterious and problematic part of a black hole. It's where our concepts of space and time ...

Could time travel be more than just a Hollywood dream? Discover how scientists say it's already happening, and why it's not what you think.

Scientists have gathered concrete evidence that time can be altered, proving that the concept of time travel exists—at least ...

We spoke with theoretical physicist Brian Greene about Einstein's theory of space-time. Many scientists believe space-time is a fundamental concept. But Greene thinks there might be something ...