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 ...

In science, there are thousands of ways to measure the world around us that the average person may never encounter. For example: Pascals to measure pressure, Candles to measure light intensity, and ...

Astronomers cannot directly weigh celestial objects like galaxies; indirect methods are necessary. Mass determination leverages the relationship between gravity and mass, utilizing orbital periods and ...

In a recent piece for my column The Universe, I wrote about the biggest black holes in the cosmos. Black holes are rather famous for being, well, black because they can gobble down even light itself.

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 ...

General relativity, our best theory of gravity, predicts that mass bends light. In gravitational lensing, light from a distant object is deflected by an intervening galaxy or cluster of galaxies. By ...

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 ...

In my previous post about a floating Saturn, I hinted that I could write about the methods we can use to find the density of Saturn. Oh, and once again, the density of Saturn is lower than the density ...

How do rogue planetary-mass objects -- celestial bodies with masses between stars and planets -- form? An international team of astronomers has used advanced simulations to show that these enigmatic ...

It is tempting to think that some materials are always heavier than other materials. For example, someone might say that metal is heavier than air. But it depends on how much of each material there is ...