How do we know the universe is 13.8 billion years old? How do we know the speed of light is 299,792,458 meters per second? How do we know there are subatomic particles that live less than a trillionth of a trillionth of a second? Studying how physicists make discoveries is the best way to understand key developments in modern physics - from quantum mechanics, to the theory of relativity, to cosmology.

In this 24-lesson course aimed at non-scientists, noted particle physicist Dr. Don Lincoln of Fermi National Accelerator Laboratory covers more than a century of progress in physics, describing exactly how scientists reach the conclusions they do. He starts with the atom, which was long hypothesized, but wasn't definitively proven until a paper by Albert Einstein in 1905. That was just the beginning, as researchers probed ever deeper into the atom's complex structure, leading to the weird findings of quantum mechanics. Meanwhile, Einstein's more famous work in relativity overturned conceptions of time and space, especially in the realm of the super-fast and ultra-massive.

Relativity and quantum theory are notoriously counterintuitive, but Dr. Lincoln shows why their conclusions must be true. He does the same for cosmology, which has advanced from the view that the Milky Way galaxy is all that exists, to the realization that there are likely a trillion of galaxies in the observable universe. Along the way, he deals with the Big Bang, black holes, dark matter, dark energy, and cosmic inflation, among other ideas. Some are purely speculative, but he points out what it would take to prove them.

The Evidence for Modern Physics is an intellectual roller-coaster ride that will amaze and enlighten. As Dr. Lincoln says, "You must wonder how we can say with such certainty that the world of the super-fast and ultra-small follow such bizarre rules. Well, you're in luck, because that's exactly what this course is about."