A proposed theory of gravity does away with dark matter, even as new astrophysical findings challenge the need for galaxies full of the invisible mystery particles.
Richard Feynman's famous diagrams weren’t just a way to do calculations. They represented a deep shift in thinking about how the universe is put together.
The search for exotic new physical phenomena is being led by huge experiments like the Large Hadron Collider. But at the other end of the spectrum lie tabletop experiments — small-scale probes of hidden dimensions, dark matter and dark energy.
Is dark energy a cosmic chameleon that can fade into its surroundings? A recent test brings the mysterious anti-gravitational force down to earth.
The astrophysicist Joshua Frieman seeks to pinpoint the mysterious substance driving the accelerating expansion of the universe.