For nearly a century, we've known that the universe is expanding, but the big surprise of the past decade was the discovery that the expansion of the universe is speeding up! Scientists turn to Albert Einstein’s remarkable ideas—that empty space has its own energy and can create yet more space—as they seek to understand the source of this acceleration, known as dark energy.

Learn more about Dark Energy using the Resources “Inside Einstein’s Universe” or explore more about Dark Energy with the UniverseForum here.