How do we know what the air is like on planets we haven't visited? This video explains how to see air from 150 light-years away.
We try to use easy-to-understand language, so we avoided technical language in this video. However, if you want to know more about a subject, you can start your adventure with the following terms:
Spectral line: A dark or bright line in a uniform and continuous spectrum. There are emission lines and absorption lines.
Spectroscopy: The study of the interaction between electromagnetic radiation and matter, with absorption or emission of radiant energy.
Exoplanet (Extrasolar planet): A planet orbiting a star other than our Sun and therefore does not belong to the solar system. The vast majority of known exoplanets have been indirectly detected by radial velocity, astrometry, transit, etc.
Diffraction grating: A device that splits light into its component parts or spectrum. They are used to study the composition of light.
Spectrometer (Spectrophotometer, Spectrograph, or Spectroscope): An instrument used to analyze the properties of light such as the light intensity, polarization, wavelength, spectral lines, etc.
If you want to know more about how the atmospheres of exoplanets are detected by absorption or emission spectroscopy, visit Sara Seager’s website.
Created by Henry Reich for MinutePhysics
Thanks to NASA’s James Webb Space Telescope project at the Space Telescope Science Institute for supporting this video.
Music by Nathaniel Schroeder
Publication: February 24, 2016