Visible Light: Big in our World, But Small in the Wave World

The electromagnetic spectrum consists of many different types of waves, from radio waves to gamma rays. One of the most familiar sections of the EM spectrum is visible light. Visible light allows us to see colors in our everyday lives, and although it's big in our world, it's very small on the EM spectrum. In fact, visible light is the smallest section of the spectrum!

Visible light is the different colors of the rainbow, and each color has a different wave frequency. The frequencies can range from 4 x 10^14 Hz (red) to 7.5 x 10^14 Hz (violet). Each color also has a different wavelength; red, the lowest, has a wavelength of 400 nanometers, and violet, the highest, has a wavelength of 700 nanometers.

When we see color, some of the waves from the Sun are reflected back to us (the color we see), and some are absorbed. If all of the colors in the spectrum were to be combined, white light would be produced. To see color, white is emitted, and then a color, maybe green, is reflected. The other colors are absorbed by the "green" object.

Visible light is used a lot in our everyday lives. Lasers are made using light, as well as infrared (waves below the frequency of red) and ultraviolet (waves above the frequency of violet) technology. Light allows nature lovers to see sunsets and rainbows. Studies have shown that a yellow-green color is best seen by humans, so many emergency vehicles and construction uniforms are changing to this color. However, there are some safety concerns and "let-downs" of visible light. Some lasers are very powerful and can be harmful to the eyes. Lightbulbs, which emit this powerful yellow-green color, are very strong at the source and can hurt our eyes, and the radiance dies down as you get further away from the source.

This is just a background of one section of the electromagnetic spectrum. For more information, visit some of the websites below.

Both pictures taken from "The Electromagnetic Spectrum" from NASA

(http://science.hq.nasa.gov/kids/imagers/ems/visible.html)

For more information/Bibliography:

"Electromagnetic Spectrum" by HyperPhysics

(http://hyperphysics.phy-astr.gsu.edu/hbase/ems3.html)

"Visible Light Waves" by NASA (http://science.hq.nasa.gov/kids/imagers/ems/visible.html)

"Laser Safety Training Guide" from Princeton University (http://web.princeton.edu/sites/ehs/laserguide/index.htm)

Mind Boggling Science!

If I were a scientist, I would be an astrophysicist. Astrophysics is "the branch of astronomy that deals with the physical and chemical processes that occur in stars, galaxies, and interstellar space." (http://www.thefreedictionary.com/astrophysicists) They use a lot of math and they have to rely on good estimation. Since there is so much to discover about space and people can't keep up with all its new discoveries, an astrophysicists job is very challenging. Check out A Day in the Life of an Astrophysicist.

I would want to be an astrophysicist because it involves a lot of math. Math and science have always been easy for me and one of my goals for high school is to discover how I can apply knowledge to the real world. Astrophysicists study physics, or why things interact in space, and this is the type of thing I really like to learn about. I love to ask questions and learn more about these amazing phenomena. Outer space is particularly interesting to me because there is so much to discover, so many questions to ask, and math and science are applied to the real world (or universe).
Since I am a "visual" learner, I would really enjoy just looking at and examining these incredible phenomena. However, an astrophysicist's job is very challenging because it is very hard to accurately measure distances and masses of objects in the universe. People cannot travel to space every day, and there is only a certain distance we can travel. Imagine this: if the Earth were the size of a golf ball, the sun would be a sphere about 15 feet in diameter. The newly discovered star Beetleguese would be six Empire state buildings tall, and there are even bigger stars than that (ChaCha.com - look at Mike's comment)! If the Earth were its normal size, then being able to meaure, let alone travel to these stars would be nearly impossible!
Astrophysicists leave quite a legacy for future generations. The information we know is quite baffling, and there is still more to know about the universe. We will always discover new knowledge about outer space, and this new knowledge really shows us how great and amazing our universe is.

To see what's happening today in the astrophysical world, look at the latest edition of The Astrophysical Journal.

Earth Golf Ball picture from "A Pebble In The Pond" blog.
Planets picture from "Uncommon Sense" journal.