The speed of light in a vacuum is approximately 299,792 kilometers per second. This means that light can travel nearly 300,000 kilometers in just one second. This incredible speed is fundamental to many areas of physics and helps us understand the universe. This speed is crucial for concepts like Einstein's theory of relativity, which shows how time and space are interconnected. It also plays a key role in technologies such as GPS and telecommunications, where the speed of light affects signal transmission and accuracy.