The Importance of Spectroscopy

Polymer Solution

The impact that spectroscopy and light has had on the world has not been recognized enough. The discovery of spectroscopy has allowed us to know so much more about astronomy and what makes up our universe. Spectroscopy is the investigation and measurement of spectra when matter interacts with electromagnetic radiation. In astronomy, we look at how light from an astronomical source interacts with different objects to form a spectra of light. There are three different kinds of spectra, a continuous spectrum, an emission spectrum, or an absorption spectrum. In a continuous spectrum, a hot light source produces light of all visible wavelengths. The spectrum shows a smooth, continuous rainbow of light. In an emission spectrum, the atoms in a warm cloud emit specific wavelengths of light. On the spectrum, we see bright emission lines at specific wavelengths on a black background. In an absorption spectrum, light from a hot source passes through a cloud of cooler gas. Atoms in the cloud absorb some of the wavelengths of light. In the spectrum, we see dark absorption lines on a continuous rainbow background. Each spectrum of an element or molecule is unique, like a fingerprint, allowing astronomers to recognize them easily. Through studying light, astronomers are allowed to determine the chemical composition of the Sun and other stars, the temperature of an object, the color of an object, and if the object is moving towards or away from us.

2 thoughts on “The Importance of Spectroscopy

  1. However, when you have a number of elements overlapping in the same spectral observation, I think it is a bit difficult to identify the elements! Now that we have digitized this process for spectral analysis, it makes the job of the astronomer much easier!


  2. TA Response:

    I agree that the importance of spectroscopy in astronomy really can’t be overstated as there really is no substitute for determine the composition of celestial objects.

    I will just add that to perform spectroscopy (that is make a spectra) scientists must spilt the light apart in some way like you prism picture illustrates. Modern instruments tend to use something called a diffraction grating to do this and how well how well the light is split is a very important limiting factor on a spectrograph’s performance.


Leave a Reply

Please log in using one of these methods to post your comment: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

Create your website at
Get started
%d bloggers like this: