Planets, like those in our solar system, form in a bottom-up process where small bits of rock and ice clump together and grow larger over time. But the heftier the planet, the harder it is to explain ...

This is a brilliant question because the notion of an orbit is counterintuitive. We know that massive objects (really, any objects with mass) gravitationally attract other massive objects; Newton’s ...

Scientists analyzing a gravitational-wave signal have discovered that a neutron star and black hole spiraled together on an oval-shaped orbit just before merging. This unusual motion, detected in the ...