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? 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 The Evidence for Modern Physics, noted particle physicist Dr. Don Lincoln of Fermi National Accelerator Laboratory covers more than a century of progress...

Investigate evidence that the expansion of the universe reversed its gradual slow-down and stepped on the accelerator 5 billion years ago. "Dark energy" is the term given to this mysterious force that is expanding space at an ever-increasing rate. Learn how this remarkable phenomenon was discovered and explore its link to the cosmological constant proposed by Einstein a century ago.

The fundamental building blocks of matter are thought to be quarks (which interact by the strong force) and leptons (which interact by the electromagnetic and weak forces). But could there be a deeper level? Explore the theory of preons, which may be even more fundamental than quarks and leptons.

As a member of the research team, Dr. Lincoln recounts the discovery of the Higgs boson, one of the major science stories of the past half century. Predicted in 1964, the Higgs particle wasn't experimentally confirmed until 2012. Trace the path to this triumph, as physicists narrowed down the properties of the elusive particle and utilized powerful particle accelerators in the hunt.

Dr. Lincoln boldly confronts the paradox of quantum entanglement, which governs the behavior of particles that share the same quantum state. Discover that the rules of quantum mechanics defy every attempt to explain what seems inexplicable -- implying, for example, that a cat could be simultaneously dead and alive in Erwin Schrödinger's famous thought experiment. Explore other spooky examples.

Follow one of the strangest turns in modern science: the discovery of the paradoxical world of light, which spawned the theory of quantum mechanics. Discover how light and matter behave as both particles and waves, and look at evidence for this curious feature of the quantum world.

Consider why mathematics is such an effective tool for describing nature. Then focus on mathematician Emmy Noether's remarkable insight that links symmetries in the equations of a physical system to conservation laws, such as the conservation of energy and conservation of momentum.

Dr. Lincoln covers general relativity, which incorporates gravity and predicts the warping of spacetime around massive objects. Study three phenomena that prove general relativity: an anomaly in the orbit of Mercury, the bending of starlight passing near the Sun, and the slowing of clocks in regions of stronger gravity.

Here, Professor Lincoln reveals the ways in which common teachings about gases and their properties are idealizations that ignore important considerations such as the size of atoms. Topics include the limitations of the Ideal Gas Law (PV=nRT) and the impo

Until 100 years ago, our Milky Way galaxy was thought to comprise the entire universe. Now we think there are roughly a trillion galaxies of various sizes and shapes in the observable universe. Investigate how astronomers reached this conclusion and how they mapped the structure and contents of the Milky Way, discovering a supermassive black hole at its center -- among other galactic attractions.