Light

Have you ever thought “What really is light?” What we now as light is really a tiny part of a bigger range called the electromagnetic spectrum. Everything in it is just waves that travel through the air. We can tell the difference between them from their wavelengths.

What we see as colors is called the visible light spectrum. It consists of red, orange, yellow, green, cyan, blue, and violet. Red’s wavelength is 625- 740 nanometers long and violet is 380- 435 nanometers long. So anything in between 740 and 380 nanometers is what we can see, but there are so many things that we can’t.

For example radio wavelengths are the size of a football field, microwaves are the size of bees, and gamma rays are the size of one atom. Gamma rays are the smallest waves, but are the most powerful. In fact gamma rays can kill living cells, so doctors use them to kill cancerous cells. They are the most energetic forms of light and are created by the hottest places in the universe. Gamma rays are the source that makes supernovas and wormholes, the things that kill massive stars.

The destruction that light can do isn’t the only amazing thing about light. Its speed is also incredible. Light is the fastest thing in the universe, in theory. It travels at 186,282 miles per second, that’s 670,616,629 miles per hour, or 5,865,696,000,000 miles per year. The distance light travels in one year is called a light year. Scientist use light years to measure distances in the universe, for example the closest star to earth (besides our sun) is around 24,000,000,000,000 miles away. That would be converted to around 4 light years. Also, light travels so fast that if the sun exploded right now, we wouldn’t know until eight minutes from now, because that’s how long the light takes to get here.

The so called “rules” of light are always changing. Like in 1999 researchers at Harvard slowed a beam of light down to 38 miles per hour. And not too long ago scientists claimed that neutrinos, a substance so small it’s not considered to have matter, moved faster than light. Also, of course, Einstein and his theory of relativity.

Light is extremely fast and just about as mysterious. Many scientists still wonder what it is and how it works; just imagine what Earth would be like without it.