Watch an animation of a black hole shooting jets of particles through a "collapsing star at nearly the speed of light" and ...

The universe has a speed limit, and it's the speed of light. Nothing can travel faster than light — not even our best spacecraft — according to the laws of physics. So, what is the speed of light?

Breakthroughs, discoveries, and DIY tips sent six days a week. Terms of Service and Privacy Policy. Back in 2018, astronomers examining the ruins of two collided ...

On one hand, the speed of light is just a number: 299,792,458 meters per second. And on the other, it’s one of the most important constants that appears in nature and defines the relationship of ...

The Parker Solar Probe, currently the fastest human-made object, travels at 0.05% the speed of light (approximately 330,000 mph). Reaching 1% the speed of light requires an immense amount of energy ...

In 1676, by studying the motion of Jupiter's moon Io, Danish astronomer Ole Rømer calculated that light travels at a finite speed. Two years later, building on data gathered by Rømer, Dutch ...

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 ...

Light is faster than anything else in the known universe, though its speed can change depending on what it's passing through. When you purchase through links on our site, we may earn an affiliate ...