Scientists pushed photons across the universe to test the speed of light—and found Einstein’s cosmic speed limit still holds ...

The universe comes with a built‑in speed cap, a hard limit that shapes everything from how stars shine to how cause and effect unfold. That limit is usually described as the speed of light, yet the ...

The most distant galaxies in this deep field image from the James Webb Space Telescope appear as small, faint dots—and are receding from us faster than the speed of light due to cosmic expansion. If ...

For the first time, physicists have simulated what objects moving near the speed of light would look like — an optical illusion called the Terrell-Penrose effect. When you purchase through links on ...

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 ...

James is a published author with multiple pop-history and science books to his name. He specializes in history, space, strange science, and anything out of the ordinary.View full profile James is a ...

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 ...

When I was a teenager, I was—shockingly, I know—deeply nerdy. At a science-fiction convention, I bought a button that read, “186,282 miles/second: Not just a good idea, it’s the law.” It was poking ...

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