From a page entitled "What is Spectroscopy?" [
"Spectroscopy pertains to the dispersion of an object's light into its
component colors (i.e. energies). By performing this dissection and
analysis of an object's light, astronomers can infer the physical
properties of that object (such as temperature, mass, luminosity and
From another page entitled "WHAT IS SPECTROSCOPY?" [
"Spectroscopy is a technique used by astronomers and physicists to
study the make-up of an object based on the light it emits." The page
goes on to say that we can get detailed information about stars from
spectroscopy "because each chemical element has a unique signature,
emitting or absorbing radiation at specific wavelengths. For example,
sodium, used in street lights, emits primarily orange light. Oxygen,
used in neon lights, emits green light."
It goes on to say that "By carefully studying how the spectrum becomes
brighter or darker at each wavelength, scientists can tell what
chemical elements are in the star and learn other information about
the object being studied, such as its temperature, density and how
fast it might be spinning."
As a piece of trivia I picked up in astronomy class, you can also tell
how fast a star is moving towards or away from you by studying the
light it emits as well. Once you have determined what light you would
expect it to emit, you examine it to see if the light you actually
observe is overly blue or overly red. If the light is more red than
would be expected, the object is moving away from you. If the light is
more blue than would be expected, the object is moving towards you.
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