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 ...

The terms weight and mass are often used incorrectly. Phrases like ‘a bag of sugar weighs 1 kg’ are not scientifically correct. This means that a 1 kg mass would be attracted to Earth by a force of 10 ...

How heavy is the Milky Way galaxy? It may seem impossible to get a sense of it from our tiny little planet, but astronomers have their ways. Now a team has used data from Hubble and the Gaia satellite ...

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 ...

Density is a way of comparing how heavy different materials are. It is a measurement of the amount of a substance contained in a certain volume. The density of any solid is the mass of the object ...