How about the Zeeman effect, in which strong magnetic fields in locations where light is emitted, will cause the spectral lines associated with emitting material to split?
The strength of the magnetic field is encoded in how broadly the line is split, allowing us to make spatially-resolved maps of the magnetic field of the Sun ("magnetograms").
Like getting the chemical composition of the emitting surface of the Sun, it's the kind of thing you'd think sounds impossible until some clever physicist figures out how to exploit it.
The strength of the magnetic field is encoded in how broadly the line is split, allowing us to make spatially-resolved maps of the magnetic field of the Sun ("magnetograms").
Like getting the chemical composition of the emitting surface of the Sun, it's the kind of thing you'd think sounds impossible until some clever physicist figures out how to exploit it.
See the little animation at the top of the page: https://en.wikipedia.org/wiki/Zeeman_effect