Editing Timeline of solar astronomy (section)

==20th century==
* 1904&nbsp;— Edward Maunder plots the first sunspot "[[butterfly diagram]]"
* 1906&nbsp;— [[Karl Schwarzschild]] explains [[Limb darkening|solar limb darkening]]
* 1908&nbsp;— [[George Hale]] discovers the [[Zeeman effect|Zeeman splitting]] of spectral lines from sunspots
* 1925&nbsp;— [[Cecilia Payne]] proposes [[Cecilia Payne#Doctorate|hydrogen is the dominant element of the Sun]], not iron
* 1929&nbsp;— [[Bernard Lyot]] invents the [[coronagraph]] and observes the [[solar corona|corona]] with an "artificial [[eclipse]]"
* 1942&nbsp;— [[J.S. Hey]] detects solar [[radio wave]]s
* 1949&nbsp;— [[Herbert Friedman]] detects solar [[X-ray]]s
* 1960&nbsp;— [[Robert B. Leighton]], [[Robert Noyes]], and [[George Simon (scientist)|George Simon]] discover solar five-[[minute]] [[oscillation]]s by observing the [[Doppler shift]]s of solar dark lines
* 1961&nbsp;— [[Horace W. Babcock]] proposes the [[Babcock Model|magnetic coiling sunspot theory]]
* 1970&nbsp;— [[Roger Ulrich]], [[John Leibacher]], and [[Robert F. Stein]] deduce from theoretical solar models that the interior of the Sun could act as a [[resonance|resonant]] [[acoustic cavity]]
* 1975&nbsp;— [[Franz-Ludwig Deubner]] makes the first accurate measurements of the period and horizontal [[wavelength]] of the five-minute solar oscillations
* 1981&nbsp;— [[NASA]] retrieves data from 1978 that shows a comet crashing into the Sun