In other words, the matter traveled at 20% the speed of light. When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works. Supermassive black holes are ...

So, you’re driving a car at half the speed of light. (Both hands on the wheel, please.) You turn on the headlights. How fast would you see this light traveling? What about a person standing by the ...

Hornof, D., Helm, V., de Dios Rodriguez, E. et al. A snapshot of relativistic motion: visualizing the Terrell-Penrose effect. Commun Phys 8, 161 (2025). https://doi ...

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 ...

Imagine this: a tiny needle hurtling toward Earth at the speed of light. At first glance, it might sound like no big deal. After all, it’s just a needle. But in reality, a projectile moving this fast ...