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 ...

This is a good question, and also a good reminder to be careful with one’s language when writing about physics! Most of the time, if you’re reading an article, what we mean by mass and rest mass is ...

It's fun to think about how we know stuff. For instance, the sun has a mass of about 2 x 10 30 kilograms. That is such an enormous mass that it's difficult to comprehend. And if it's so difficult for ...

There are quite a few fundamental constants. These are things like the speed of light (c) the charge on an electron (e), and the Planck constant (h). These constants are determined with some type of ...

Newton's Second Law states that force equals mass times acceleration. This can be investigated using a set-up like this one. You can use this set-up to investigate how changing two separate factors, ...