The grandfather paradox is just one of the thorny logical problems that arise with the concept of time travel. But one physicist says he has resolved them.

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 ...

First conceived as a result of Einstein’s general theory of relativity, closed timelike curves are the hypothetical results of rotating gravity wells being able to basically drag spacetime (which is ...

matter tells space-time how to curve”. But this short description from the physicist John Wheeler hides a more complex and profound truth. Besides quantum theory, general relativity is one of ...