The word dust comes up often in descriptions of galaxies and elsewhere. What is the nature of dust?
Isaac Turiel
Berkeley, California
To most people, dust can be any combination of small particles of soil, rock, human skin, human or animal dander, pollen, and tiny bits of fiber. But space dust is different from the dust we’re familiar with here on Earth.
Astronomers are also talking about small grains of material when they talk about dust, but unlike on Earth, a majority of those g