Light Basics Types of Light Light Gallery The EM Spectrum


Objective: Match the size of different light wavelengths with the sizes of different objects

Light Gives Us Information About Objects in Space:
For example, by studying infrared light from a nebula, we can tell how hot its gases are. By studying extreme ultraviolet light from a white dwarf star we can study what materials it is made of. So, by studying all the different types of light, scientists have been able to discover that the universe is a far more vibrant environment than the eye can see. Data gathered in non-visible wavelengths allows both a better understanding of known objects and the discovery of new objects, such as gamma-ray bursters, that radiate all their energy outside the range of visible light.

But How Do Astronomers Decide What Type of Light is Coming from these Objects in Space?
Different types of light differ in wavelength . Remember from "Light Basics", this is the distance from the peak to peak or trough to trough of a wave. For example, the wavelength of extreme ultraviolet light may measure 100 to 1000 angstroms,  and visible light has wavelengths that range from about 4,000 to 7,000 angstroms. How long is 100 angstroms or 4,000 angstroms? And just what is an "angstrom?" Keep on reading and find out!

How Long Is An Angstrom?
Astronomers use a tiny unit of distance called the "angstrom" to measure wavelengths. Angstroms are abbreviated " Å" and named after the Swedish physicist A.J. Angstrom. One angstrom equals .00000001 cm, a very tiny length. That means that visible light may have a wavelength of 4,000 angstroms or about .00004 cm. One angstrom is pretty small compared to our own body size. 


But just how small is it? Take a look at this next set of images. See if you can find the closest object in length to a visible light wavelength.


Light Basics Types of Light Light Gallery The EM Spectrum


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