The speed of light is constant, or so textbooks say. But some scientists are exploring the possibility that this cosmic speed limit changes, a consequence of the nature of the vacuum of space. The ...

The speed of light is a fundamental constant, approximately 299,792,458 meters per second. It's the same for all observers and hasn't changed measurably over billions of years. Nothing can travel ...

When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works. The speed of light traveling through a vacuum is exactly 299,792,458 meters (983,571,056 feet) ...

Seeing flashing lights in your eye could indicate many different health conditions. Treatment will depend on the underlying cause, but you’ll definitely want to see an eye doctor as soon as possible.

Seeing flashing lights in the corner of one or both eyes can occur with migraine or result from trauma, detached retina, or other problems. The flashes of light may vary in shape, color, frequency, ...