Speed of Light
Since ancient times, philosophers and scholars have sought to understand light. In addition to trying to discern its basic properties (i.e. what is it made of – particle or wave, etc.) they have also sought to make finite measurements of how fast it travels. Since the late-17th century, scientists have been doing just that, and with increasing accuracy. In so doing, they have gained a better understanding of light’s mechanics and the important role it plays in physics, astronomy and cosmology. Put simply, light moves at incredible speeds and is the fastest moving thing in the Universe. Its speed is considered a constant and an unbreakable barrier, and is used as a means of measuring distance. But just how fast does it travel? Light travels at a constant speed of 1,079,252,848.8 (1.07 billion) km per hour. That works out to 299,792,458 m/s, or about 670,616,629 mph (miles per hour). To put that in perspective, if you could travel at the speed of light, you would be able to circumnavigate the globe approximately seven and a half times in one second. Meanwhile, a person flying at an average speed of about 800 km/h (500 mph), would take over 50 hours to circle the planet just once.