The speed of light is constant, or so textbooks say ... along with the permittivity of space to magnetic fields, governs the speed of light. Some scientists are a bit skeptical, though.

The real part of permittivity, also called the dielectric constant, represents the material’s ability ... to control a thermal chamber and heat-resistant cable kits. Measuring magnetic materials Like ...

A non-constant speed of light could mean ... and its measured value, along with the permittivity of space to magnetic fields, governs the speed of light. Some scientists are a bit skeptical ...