Neutron star and black hole masses in binary systems are calculable using Kepler's laws of motion, based on orbital parameters and object speeds. Merging neutron stars or black holes emit ...

How do we know the mass of a planet originally appeared on Quora - the knowledge sharing network where compelling questions are answered by people with unique insights. Answer by Geoffrey Widdison on ...

As the New Horizons spacecraft is approaching Pluto, it's getting some great shots. The animation below shows Pluto and Charon as they orbit each other. When a planet (or dwarf planet) has a satellite ...