How can spectra tell us what things are made of?

Stars and planets are too far away for a human to touch, yet we know what they are made of. Spectra make this possible! Let’s investigate how.

What is the Sun made of?

The Sun’s absorption lines tell us what elements are present in its gas.

For example, we know that hydrogen is the most common element in a star.

Spectrum Tool. Compare the spectra to identify what the Sun is made of.

  1. Use the dropdown menu to select the hydrogen (emission) spectrum.
  2. Identify three distinct wavelengths where absorption lines appear in both the Sun’s spectrum (top) and emission lines appear in the hydrogen spectrum (bottom).
  3. Use the dropdown menu to compare other atomic spectra with the Sun. Identify one other element that is present in the Sun based on the absorption and emission spectra.

Note: A particular element like hydrogen can either absorb or emit light. Either way, the lines will occur at the same specific set of wavelengths and can be used as the “fingerprint” for that element.

Spectrum Notebook. Write your answers in the What can we know about Sun from its spectra? section.

Source 1:
Stars — Sun
Brightness
Full-intensity spectrum backgroundTransparency increases or decreases based on chart intensity, hiding or revealing the background
Left axis ticks
Spectrum intensity vs wavelength chart
Bottom axis ticks
Wavelength (Microns)
Source 2:
 
Brightness
Full-intensity spectrum backgroundTransparency increases or decreases based on chart intensity, hiding or revealing the background
Left axis ticks
Spectrum intensity vs wavelength chart
Bottom axis ticks
Wavelength (Microns)
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