Scientists may have finally found the universe’s missing matter - hidden in invisible hydrogen gas far beyond galaxies.

Students are introduced to the idea that matter is composed of atoms and molecules that are ... experiment with and observe the heating and cooling of a solid, liquid, and gas.

Astronomers tallying up all the normal matter—stars, galaxies and gas—in the universe today have come up embarrassingly short ...

Solids, liquids and gases are called the three states of matter. Liquids can flow or be poured easily. They are not easy to hold. Liquids change their shape depending on the container they are in.

The universe's missing matter may have finally been found.Astronomers think regular matter — that is, the stuff that isn't ...