image of extra dimensions

Big Mysteries: Extra Dimensions

August 17, 2017

Extra dimensions, which may well be an incorrect hypothesis, are one possible explanation for why gravity is so much weaker than the other forces.  In this video, Great Courses professor Dr. Don Lincoln explains it all with the help of a talking rabbit. […]


The Origin of Mass

August 3, 2017

Sophisticated consumers of science have heard that the Higgs boson is the origin of mass for ordinary matter. This is true, to a degree…  […]


Wave or Particle—What Is Light?

July 15, 2017

Light propagates through space as a continuous wave, but also exchanges energy in the form of discrete particles. So, wave or particle—what is light? […]

Photograph of Albert Einstein during a lecture in Vienna in 1921
History of Science

Einstein’s Experimental Elevator

December 14, 2016

In 1907, physicist Albert Einstein devised what we now call the “elevator” thought experiment, in which he dreamed up the idea of having an entire physics laboratory inside a falling elevator. The result of Einstein’s experimental elevator experiment was nothing less than the principles underlying the General Theory of Relativity. […]

Dark matter in the center of galaxy cluster Abell 520

Dark Matter: MACHOs or WIMPs?

December 14, 2016

By Sean Carroll, PhD, California Institute of Technology In the hunt for dark matter, several candidates could make up this mysterious substance. One of the more […]

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