Originally published at: https://bigideas.network/what-is-ordinary-matter/
Every new generation of scientists push against the limits of what we know about the universe, and when they do so it always seems to become more vast.
Early humans once no doubt thought that the river valleys in which they lived were all that there was in the universe.
Thousands of years later, we believed that the Earth lay at the center of the universe, until we discovered that it was one planet among many around our Sun.
In the 17th Century, we found that our Sun was one among billions of others just like it in the Milky Way galaxy.
In 1923, we discovered that the Milky Way was one among billions of galaxies, which outnumber every human being who has ever lived…