The universe comes with a built‑in speed cap, a hard limit that shapes everything from how stars shine to how cause and ...

Addressing a controversy first raised around 1910, two physicists have performed experiments with the aid of an engineer that validate anew the special theory of relativity’s limitations on the speed ...

The curious minds at What If explore whether humans could ever travel faster than the speed of light, investigating physics, ...

Imagine you’re in a car driving across the country watching the landscape. A tree in the distance gets closer to your car, passes right by you, then moves off again in the distance behind you. Of ...

Einstein’s claim that the speed of light is constant has survived more than a century of scrutiny—but scientists are still daring to test it. Some theories of quantum gravity suggest light might ...

Relativistic physics imposes one of the most frustrating limitations predicted by science. It tells us that an inescapable speed limit exists in the universe: we can't go faster than the speed of ...

The hypothetical faster-than-light particle known as the tachyon may marry with the special theory of relativity, according to a team of physicists, making its existence more plausible. Tachyons are a ...

The Sagnac effect, first observed over a century ago, remains central to our understanding of relativistic kinematics and the operational definitions of simultaneity. Fundamentally, this effect arises ...

Science fiction authors and readers dream of travelling at the speed of light, but Einstein tells us we can’t. You might think that’s an arbitrary rule, but [FloatHeadPhysics] shows a different way to ...

If there is an absolute law in the universe, it’s that nothing can travel faster than the speed of light. For science-fiction enthusiasts, that’s a bit depressing. Space is big, and while the speed of ...

In Newtonian physics, gravity was thought to be instantaneous. But in Albert Einstein’s general theory of relativity, the speed of light, c, is the fastest possible speed for any interaction that ...