Lavoisier's finding laid the foundation for modern chemistry and revolutionized science. The Law of Conservation of Mass holds true ... up living and nonliving matter are very old and each atom ...

There's a significant imbalance between matter and antimatter in our universe, but a strange particle called "the Majoron" ...

If something seems light for its size (like a bag of cotton or pumice rock), then we say it has low density. Mass is the amount of matter in an object. Volume is how much space the object takes up.

However, scientists don’t see enough visible mass in many galaxies in the universe, yet gravity keeps such galaxies intact. How’s this even possible? This is where the concept of dark matter ...

Perhaps one of the most surprising discoveries of the 20th century was that this ordinary, or baryonic, matter makes up less than 5 percent of the mass of the universe. The rest of the universe ...

Heavy dark matter might disrupt current physics models, potentially changing our understanding of the universe.

The cores of galaxies may not be made of what we thought, new research suggests — they could hold one giant, invisible star ...

After decades of study, scientists sound genuinely optimistic about the possibility of detecting primordial black holes, which might explain dark matter.

A teaspoonful of their matter would weigh as much on Earth as an elephant—5.5 tons. White dwarfs typically have a radius just .01 times that of our own sun, but their mass is about the same.