The Mystery of Light | How Light Changes our Lives

The Mystery of Light | How Light Changes our Lives

Daniel Oh, Journalist

Believe it or not, the official measured speed of light is 299,792,458 meters per second. 


For a long time, people thought the speed of light was infinite, covering any amount of space instantly. It wasn’t until 1676 that light’s finite speed was proved. Danish astronomer Ole Roemer observed that Jupiter’s moons’ eclipses took place sooner than predicted when Earth was closer to Jupiter rather than the eclipses taking place later when Earth was farther away. Ole predicted this was because light took time to travel to our eyes. Measuring the speed of light is difficult, and a lot of people in the past can agree with that. Galileo was the first one to attempt it, but realized that the speed of light was too fast to measure, leading people to conclude that the speed of light was infinite. Ole Romer eventually determined the exact speed of light by studying Jupiter’s moons. 


Light exists in the state between a particle and a wave. For years, this puzzled scientists. What was shocking was that light in some cases interacted as a particle, and in other cases worked as a wave. This is proved by quantum mechanics, allowing light to exist in both states at once. 


We see things with light. It enters our eyes, and our brain takes all of the information and transfers it into reality. Light bounces off of things, and eventually shoots into our eyes. Without light, we wouldn’t be able to see anything. Shadows are the absence of light. When an object prevents light from hitting a surface, we see the space darkly because less light bounces off of it into our eyes. If you’re in an enclosed room with no light, you can’t see anything because there is no light for your eyes to take in. 


Since light takes time to travel to our eyes, looking at things is seeing the version of something some time ago. If you were far enough back and zoomed in on Earth, you would see dinosaurs or cavemen. What’s even stranger is seeing something that isn’t actually there. If a star emits light, and in a thousand years, travels into our eyes, we will see the star. However, if the star dies in those thousand years, the star won’t actually be there, but we on Earth see it clearly. These concepts of “ghost stars” are actually more common than you might think. 


You may not realize it, but you experience the speed of light way more than you might think. The next time you look at the night sky or see vibrant colors, you can thank light for letting you experience life with sight.