Timeline of solar astronomy
Encyclopedia
9th century
- 850 — Ahmad ibn Muhammad ibn Kathīr al-Farghānī (Alfraganus) gives values for the obliquity of the eclipticEclipticThe ecliptic is the plane of the earth's orbit around the sun. In more accurate terms, it is the intersection of the celestial sphere with the ecliptic plane, which is the geometric plane containing the mean orbit of the Earth around the Sun...
, the precessional movement of the apogeesApsisAn apsis , plural apsides , is the point of greatest or least distance of a body from one of the foci of its elliptical orbit. In modern celestial mechanics this focus is also the center of attraction, which is usually the center of mass of the system...
of the SunSunThe Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
10th century
- 900–929 — Muhammad ibn Jābir al-Harrānī al-Battānī (Albatenius) discovers that the direction of the Sun's eccentricityOrbital eccentricityThe orbital eccentricity of an astronomical body is the amount by which its orbit deviates from a perfect circle, where 0 is perfectly circular, and 1.0 is a parabola, and no longer a closed orbit...
is changing - 950–1000 — Ibn YunusIbn YunusIbn Yunus was an important Egyptian Muslim astronomer and mathematician, whose works are noted for being ahead of their time, having been based on meticulous calculations and attention to detail.The crater Ibn Yunus on the Moon is named after...
observes more than 10,000 entries for the Sun's position for many years using a large astrolabeAstrolabeAn astrolabe is an elaborate inclinometer, historically used by astronomers, navigators, and astrologers. Its many uses include locating and predicting the positions of the Sun, Moon, planets, and stars, determining local time given local latitude and longitude, surveying, triangulation, and to...
with a diameter of nearly 1.4 metres
11th century
- 1031 — Abū al-Rayhān al-Bīrūnī calculates the distance between the Earth and the Sun in his Canon Mas’udicus
17th century
- 1613 — Galileo GalileiGalileo GalileiGalileo Galilei , was an Italian physicist, mathematician, astronomer, and philosopher who played a major role in the Scientific Revolution. His achievements include improvements to the telescope and consequent astronomical observations and support for Copernicanism...
uses sunspotSunspotSunspots are temporary phenomena on the photosphere of the Sun that appear visibly as dark spots compared to surrounding regions. They are caused by intense magnetic activity, which inhibits convection by an effect comparable to the eddy current brake, forming areas of reduced surface temperature....
observations to demonstrate the rotation of the SunSunThe Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields... - 1619 — Johannes KeplerJohannes KeplerJohannes Kepler was a German mathematician, astronomer and astrologer. A key figure in the 17th century scientific revolution, he is best known for his eponymous laws of planetary motion, codified by later astronomers, based on his works Astronomia nova, Harmonices Mundi, and Epitome of Copernican...
postulates a solar windSolar windThe solar wind is a stream of charged particles ejected from the upper atmosphere of the Sun. It mostly consists of electrons and protons with energies usually between 1.5 and 10 keV. The stream of particles varies in temperature and speed over time...
to explain the direction of cometCometA comet is an icy small Solar System body that, when close enough to the Sun, displays a visible coma and sometimes also a tail. These phenomena are both due to the effects of solar radiation and the solar wind upon the nucleus of the comet...
tails
19th century
- 1802 — William Hyde WollastonWilliam Hyde WollastonWilliam Hyde Wollaston FRS was an English chemist and physicist who is famous for discovering two chemical elements and for developing a way to process platinum ore.-Biography:...
observes dark lines in the solar spectrumElectromagnetic spectrumThe electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation. The "electromagnetic spectrum" of an object is the characteristic distribution of electromagnetic radiation emitted or absorbed by that particular object.... - 1814 — Joseph FraunhoferJoseph von FraunhoferJoseph von Fraunhofer was a German optician. He is known for the discovery of the dark absorption lines known as Fraunhofer lines in the Sun's spectrum, and for making excellent optical glass and achromatic telescope objectives.-Biography:Fraunhofer was born in Straubing, Bavaria...
systematically studies the dark lines in the solar spectrum - 1834 — Hermann HelmholtzHermann von HelmholtzHermann Ludwig Ferdinand von Helmholtz was a German physician and physicist who made significant contributions to several widely varied areas of modern science...
proposes gravitationGravitationGravitation, or gravity, is a natural phenomenon by which physical bodies attract with a force proportional to their mass. Gravitation is most familiar as the agent that gives weight to objects with mass and causes them to fall to the ground when dropped...
al contraction as the energy source for the Sun - 1843 — Heinrich SchwabeHeinrich SchwabeSamuel Heinrich Schwabe a German astronomer remembered for his work on sunspots.Schwabe was born at Dessau. At first an apothecary, he turned his attention to astronomy, and in 1826 commenced his observations on sunspots. Schwabe was trying to discover a new planet inside the orbit of Mercury...
announces his discovery of the sunspot cycle and estimates its period to be about a decadeDecadeA decade is a period of 10 years. The word is derived from the Ancient Greek dekas which means ten. This etymology is sometime confused with the Latin decas and dies , which is not correct.... - 1852 — Edward SabineEdward SabineGeneral Sir Edward Sabine KCB FRS was an Irish astronomer, geophysicist, ornithologist and explorer.Two branches of Sabine's work in particular deserve very high credit: Determination of the length of the seconds pendulum, a simple pendulum whose time period on the surface of the Earth is two...
shows that sunspot number is correlated with geomagnetic field variations - 1859 — Richard Carrington discovers solar flareSolar flareA solar flare is a sudden brightening observed over the Sun surface or the solar limb, which is interpreted as a large energy release of up to 6 × 1025 joules of energy . The flare ejects clouds of electrons, ions, and atoms through the corona into space. These clouds typically reach Earth a day...
s - 1860 — Gustav KirchhoffGustav KirchhoffGustav Robert Kirchhoff was a German physicist who contributed to the fundamental understanding of electrical circuits, spectroscopy, and the emission of black-body radiation by heated objects...
and Robert BunsenRobert BunsenRobert Wilhelm Eberhard Bunsen was a German chemist. He investigated emission spectra of heated elements, and discovered caesium and rubidium with Gustav Kirchhoff. Bunsen developed several gas-analytical methods, was a pioneer in photochemistry, and did early work in the field of organoarsenic...
discover that each chemical elementChemical elementA chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. Familiar examples of elements include carbon, oxygen, aluminum, iron, copper, gold, mercury, and lead.As of November 2011, 118 elements...
has its own distinct set of spectral lineSpectral lineA spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from a deficiency or excess of photons in a narrow frequency range, compared with the nearby frequencies.- Types of line spectra :...
s - 1861 — Gustav SpörerGustav SpörerFriederich Wilhelm Gustav Spörer was a German astronomer.He is noted for his studies of sunspots and sunspot cycles. In this regard he is often mentioned together with Edward Maunder. Spörer was the first to note a prolonged period of low sunspot activity from 1645 to 1715...
discovers the variation of sun-spot latitudeLatitudeIn geography, the latitude of a location on the Earth is the angular distance of that location south or north of the Equator. The latitude is an angle, and is usually measured in degrees . The equator has a latitude of 0°, the North pole has a latitude of 90° north , and the South pole has a...
s during a solar cycle, explained by Spörer's lawSpörer's lawSpörer's law predicts the variation of sunspot latitudes during a solar cycle. It was discovered by the English astronomer Richard Christopher Carrington around 1861. Carrington's work was refined by the German astronomer Gustav Spörer.... - 1863 — Richard Carrington discovers the differential nature of solar rotation
- 1868 — Pierre Janssen and Norman Lockyer discover an unidentified yellow line in solar prominenceSolar prominenceA prominence is a large, bright feature extending outward from the Sun's surface, often in a loop shape. Prominences are anchored to the Sun's surface in the photosphere, and extend outwards into the Sun's corona...
spectra and suggest it comes from a new element which they name "heliumHeliumHelium is the chemical element with atomic number 2 and an atomic weight of 4.002602, which is represented by the symbol He. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table...
" - 1893 — Edward Maunder discovers the 1645-1715 Maunder sunspot minimum
20th century
- 1904 — Edward Maunder plots the first sunspot "butterfly diagramButterfly diagramIn the context of fast Fourier transform algorithms, a butterfly is a portion of the computation that combines the results of smaller discrete Fourier transforms into a larger DFT, or vice versa . The name "butterfly" comes from the shape of the data-flow diagram in the radix-2 case, as described...
" - 1906 — Karl SchwarzschildKarl SchwarzschildKarl Schwarzschild was a German physicist. He is also the father of astrophysicist Martin Schwarzschild.He is best known for providing the first exact solution to the Einstein field equations of general relativity, for the limited case of a single spherical non-rotating mass, which he accomplished...
explains solar limb darkening - 1908 — George Hale discovers the Zeeman splittingZeeman effectThe Zeeman effect is the splitting of a spectral line into several components in the presence of a static magnetic field. It is analogous to the Stark effect, the splitting of a spectral line into several components in the presence of an electric field...
of spectral lines from sunspots - 1925 — Cecilia Payne proposes hydrogen is the dominant element of the sun, not iron
- 1929 — Bernard LyotBernard LyotBernard Ferdinand Lyot was a French astronomer.His interest in astronomy started in 1914. He soon acquired a telescope and soon upgraded to a . From graduation in 1918 until 1929, he worked as a demonstrator at the Ecole Polytechnique...
invents the coronagraphCoronagraphA coronagraph is a telescopic attachment designed to block out the direct light from a star so that nearby objects – which otherwise would be hidden in the star's bright glare – can be resolved...
and observes the coronaCoronaA corona is a type of plasma "atmosphere" of the Sun or other celestial body, extending millions of kilometers into space, most easily seen during a total solar eclipse, but also observable in a coronagraph...
with an "artificial eclipseEclipseAn eclipse is an astronomical event that occurs when an astronomical object is temporarily obscured, either by passing into the shadow of another body or by having another body pass between it and the viewer...
" - 1942 — J.S. Hey detects solar radio waveRadio WaveRadio Wave may refer to:*Radio frequency*Radio Wave 96.5, a radio station in Blackpool, UK...
s - 1949 — Herbert FriedmanHerbert FriedmanHerbert Friedman was an American pioneer in the application of sounding rockets to solar physics, aeronomy, and astronomy. He was also a statesman and public advocate for science...
detects solar X-rayX-rayX-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...
s - 1960 — Robert B. Leighton, Robert Noyes, and George Simon discover solar five-minuteMinuteA minute is a unit of measurement of time or of angle. The minute is a unit of time equal to 1/60th of an hour or 60 seconds. In the UTC time scale, a minute on rare occasions has 59 or 61 seconds; see leap second. The minute is not an SI unit; however, it is accepted for use with SI units...
oscillationOscillationOscillation is the repetitive variation, typically in time, of some measure about a central value or between two or more different states. Familiar examples include a swinging pendulum and AC power. The term vibration is sometimes used more narrowly to mean a mechanical oscillation but sometimes...
s by observing the Doppler shifts of solar dark lines - 1961 — Horace W. BabcockHorace W. BabcockHorace Welcome Babcock was an American astronomer. He was the son of Harold D. Babcock.He invented and built a number of astronomical instruments, and in 1953 was the first to propose the idea of adaptive optics. He specialized in spectroscopy and the study of magnetic fields of stars...
proposes the magnetic coiling sunspot theory - 1970 — Roger Ulrich, John Leibacher, and Robert F. Stein deduce from theoretical solar models that the interior of the Sun could act as a resonantResonanceIn physics, resonance is the tendency of a system to oscillate at a greater amplitude at some frequencies than at others. These are known as the system's resonant frequencies...
acoustic cavity - 1975 — Franz-Ludwig Deubner makes the first accurate measurements of the period and horizontal wavelengthWavelengthIn physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the wave's shape repeats.It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a...
of the five-minute solar oscillations - 1981 — NASANASAThe National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
retrieves data from 1978 that shows a comet crashing into the Sun
21st century
- 2004 — largest solar flareSolar flareA solar flare is a sudden brightening observed over the Sun surface or the solar limb, which is interpreted as a large energy release of up to 6 × 1025 joules of energy . The flare ejects clouds of electrons, ions, and atoms through the corona into space. These clouds typically reach Earth a day...
ever recorded occurs