Kennedy Jr.’s testimony at the Senate Finance Committee hearing, even invoking the space-time continuum to fact-check President Donald Trump’s nominee for Health and Human Services Secretary.

Teenagers spend an average of six to eight hours a day in screen-based leisure, and even Bill Gates is troubled by how it may ...

In it, he suggested that gravity is not a force, as Newton had believed, but the result of a curvature of the space-time continuum -- the four dimensional world in which we live. He used a thought ...