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June 26, 2009

Spectroscopy (The Color of the Universe)

In space sciences, there are few things more important than light. Spectroscopy is the study of light. Almost everything we know comes from light. We build bigger telescopes to gather more light, and put telescopes in space to see in different types of light. Because of this, astronomers have figured out how to squeeze as much information out of every photon we can.

Light is cool: it lets you see our world every day. But the light we see is just a small sliver of the many types of light that are out there. The light we can see with our eyes we call visible light (no surprise there). Think of this light as the rainbow, with violet at one end and red at the other. If we could continue our rainbow into the other colors of light, we would see a very different world.

Past the red of our rainbow, we get the infrared. This is weird because things that are hotter give off more infrared light. So we can use infrared light to tell the temperature of objects. You are a flashlight in the infrared.

Keep going past the infrared and you get into the microwave light. This is the same color of light that is used to cook your food in that iconic box. Microwaves are also used for communication and studying the first moments after the big bang.

Radio light is past even the microwaves. Radio light is used in lots of commutation applications. Everything from your car radio to cell phones use radio light. The reason that it is so useful is that radio light passes though almost everything without a problem. Radio light passes though your house like visible light passes though a window.

All of these colors of light have less energy then our visible light. Light is a wave, kind of like sound. You can think of these colors of light as the low pitches. The "high-pitched", more energetic light are the colors past violet. These are also the dangerous colors of light.

The first of these is ultraviolet. This is the color of light that will give you a sunburn. Lucky for us, most ultraviolet light is blocked by our atmosphere. Otherwise, you would get a sunburn on your insides.

Next are the X-rays. These are what doctors use in X-ray and CT scans. The amount of X-rays you get from a trip to the doctor is harmless, but in high doses X-rays can be very dangerous. Lucky for us our atmosphere absorbs X-rays. In astronomy, X-rays are produced by some of the most exciting places in the universe like black holes and supernovae.

Last on our tour are the Gamma rays. Gamma rays can be deadly under certain circumstances. In astronomy, one of the most exciting explosions are gamma ray bursts (GRB).

Light is amazing. In astronomy, many times all we get is the light. All of these different colors of light have taught us something different about the universe, and we continue to learn from each of them.

Image Credit- Wikipedia
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