In the late 1800s, no one knew what light was. Everyone knew it behaved like a wave some of the time, but all waves need to travel through some propagation medium. This propagation medium was called ...

Einstein’s explanation of special relativity, delivered in his 1905 paper On the Electrodynamics of Moving Bodies focuses on demolishing the idea of ‘absolute rest’, exemplified by the ...

As the 19th century came to a close, physicists were feeling pretty satisfied with the state of their science. The great edifice of physical theory seemed complete. A few minor experiments remained to ...

This is an easier one than dark matter vs. modified gravity. As mentioned, I'm going to be on Science Friday today, and they asked me to contribute a guest blog post, which I'm cross-posting below.

Special relativity is one of the most strongly validated theories humanity has ever devised. It is central to everything from space travel and GPS to our electrical power grid. Central to relativity ...

Brendan Foster describes renewed interest in the luminiferous aether (2 November, p 32). For all its shortcomings, the aether was one of the most productive scientific ideas of all time. Many ...

“What is there in places empty of matter?” asked Isaac Newton in 1706. Nature abhors a vacuum, and so do people. For as long as we have considered the universe, we have sought to fill its emptiness.

“…upon this simple system of many colors is based the manifold and infinitely varied investigation of all things.” —Zosimos of Panopolis (ca. 250 CE ...