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The First Photograph of the Sun, was made on 2 April 1845 in Paris, France. Credit: Léon Foucault and Hippolyte Fizeau.{{free media}}

Heliology is the science of Helios, Sol, otherwise known as the Sun.

Theoretical heliology[edit]

This is an image of the sun taken from the surface of the Earth through a camera lens. Credit: Lykaestria.

Def. the "scientific study of the Sun"[1] is called heliology.

Def. the "star at the center of the Solar System, represented in astronomy and astrology by ⨀"[2] is called the Sun.

Def. the "star that the Earth revolves around and from which it receives light and warmth.[3]"[4] is called the sun.


This "neutrino image" of the Sun is produced by using the Super-Kamiokande to detect the neutrinos from nuclear fusion coming from the Sun. Credit: R. Svoboda and K. Gordan (LSU).

Gamma rays[edit]

The Sun is seen in gamma rays by COMPTEL in June 15, 1991. Credit: COMPTEL team, University of New Hampshire.

The Sun is seen in gamma rays by COMPTEL during a June 15, 1991, solar flare. The Sun is ordinarily not known to produce gamma rays, but during this solar flare, streams of neutrons poured into the intrastellar medium to create gamma rays. This image provided the first evidence that the Sun can accelerate particles for several hours. This phenomenon was not observed before CGRO and represents a new understanding of solar flares.


The GOES 14 spacecraft carries a Solar X-ray Imager that took this image of the Sun during the most recent quiet period. The Sun appears dark because of the wavelength band of observation. Credit: NOAA/Space Weather Prediction Center and the NWS Internet Services Team.


This is a visual image of the Sun. Credit: Big Bear Solar Observatory.

At the right is a visual image of the Sun.


This is an image of the Sun using an H I violet band pass filter. Credit: NASA.

The image at the right is of the Sun using an H I violet band pass filter.


The image shows the Sun in the Ca K line followed by a false-color inversion. Credit: Alan Friedman.

At the right is an image of the Sun through a Ca K extreme violet filter inverted through false color.


This is a visual image of the Sun with some sunspots visible. The two small spots in the middle have about the same diameter as our planet Earth. Credit: NASA.

At the right is a visual image of the Sun with some sunspots visible. The two small spots in the middle have about the same diameter as our planet Earth.


This is a red image of the Sun taken through a solar telescope. Credit: Totallyhaywire2.

The image at right here is a red image taken through a solar telescope.


This is an infrared image of the Sun. Credit: National Solar Observatory, Kitt Peak, Arizona USA.

At the right is an infrared image of the Sun.


The quiet Sun at 4.6 GHz imaged by the VLA with a resolution of 12 arcsec, or about 8400 km on the surface of the Sun. Credit: NRAO.

At right is a radio image of the Sun at 4.6 GHz. "The brightest discrete radio source is the Sun, but it is much less dominant than it is in visible light. The radio sky is always dark, even when the Sun is up, because atmospheric dust doesn't scatter radio waves, whose wavelengths are much longer than the dust particles."[5]

"The quiet Sun at 4.6 GHz imaged by the [Very Large Array] VLA with a resolution of 12 arcsec, or about 8400 km on the surface of the Sun. The brightest features (red) in this false-color image have brightness temperatures ~ 106 K and coincide with sunspots. The green features are cooler and show where the Sun's atmosphere is very dense. At this frequency the radio-emitting surface of the Sun has an average temperature of 3 x 104 K, and the dark blue features are cooler yet. The blue slash crossing the bottom of the disk is a feature called a filament channel, where the Sun's atmosphere is very thin: it marks the boundary of the South Pole of the Sun. The radio Sun is somewhat bigger than the optical Sun: the solar limb (the edge of the disk) in this image is about 20000 km above the optical limb."[5]


The Sun is observed through a telescope with an H-alpha filter. Credit: Marshall Space Flight Center, NASA.

"In the 1920s, Payne [3] and Russell [4] reported that the Sun’s atmosphere consisted mostly of hydrogen (H) and helium (He), but Hoyle [5] notes that he and others "in the astronomical circles to which I was privy" (p. 153) continued until after the Second World War to believe that the Sun was made mostly of iron. Then Hoyle notes that "much to my surprise" (p. 154), the high-hydrogen, low-iron model was suddenly adopted without opposition."[6]

For comparison with other stars, the Sun has the following properties:

  • The effective temperature of the surface of the Sun's photosphere is 5,778 K.[7]
  • Metallicity, Z = 0.0122[8], "lowest seismic estimate of solar metallicity is Z = 0.0187 [to the] highest is Z = 0.0239, with uncertainties in the range of 12%-19%."[9]
  • Stellar companion: Jupiter at present, perhaps Uranus in some larger form previously[10]
  • Age: 4.57 billion years[11]
  • B-V = 0.656 ± 0.005[12]
  • Rotation rate: 7.189 x 103 km h-1 (at the equator), equatorial circumference of 4,379,000 kilometres divided by sidereal rotation period of 609.12 hours[13]


Solar eruption, extreme ultraviolet emission line at 30.4 nm is from singly ionized Helium, or He II, and corresponds to a temperature of approximately 50,000 degrees Celsius. Credit: NASA/SDO AIA Team.

Solar eruption in the image on the right was captured by the Solar Dynamics Observatory using the extreme ultraviolet emission line at 30.4 nm of singly ionized Helium, or He II, and corresponds to a temperature of approximately 50,000 K.

Stellar surface fusion[edit]

Diagram illustrates deuterium-tritium fusion in three steps. Credit: Panoptik.

"Concerning the particles which interact at the Sun, evidence for accelerated 3He enrichment was obtained from the detection (Share & Murphy 1998) of a gamma-ray line at 0.937 MeV produced by the reaction 16O(3He,p)18F".[14]

For "essentially all of [some 20] flares 3He/4He can be as large as 0.1, while for some of them values as high as 1 are possible. In addition, [...] for the particles that interact and produce gamma rays, 3He enrichments are present for both impulsive and gradual flares."[14]

"Plasma is the medium for magnetically or inertially-confined controlled thermonuclear fusion. A plasma of deuterium and tritium ions heated to a temperature of 108 degrees Kelvin undergoes thermonuclear burn, producing energetic helium ions and neutrons from fusion reactions."[15]

On the right is a diagram illustrating deuterium-tritium fusion in three steps:

  1. the D and T accelerating towards each other at thermonuclear speeds,
  2. the creation of an unstable He-5 nucleus,
  3. the ejection of a neutron and repulsion of the He-4 nucleus.

The "energy" is released in the form of the velocities of the constituent parts being thrown apart, or radiated apart.


Relief shows Helios, sun god in the Greco-Roman mythology. Credit: Gryffindor.{{free media}}

There is "an Egyptian ostrakon (first century B.C.) cited by Franz Boll: the ostrakon identifies the planet Saturn as the great god Re.4",[16] where 4 lists Boll, Kronos-Helios, 343, R8.[17]

"But many scholars notice that among the Greeks and Latins there prevailed a mysterious confusion of the "sun" (Greek helios, Latin sol) with the outermost planet [Saturn]. Thus the expression "star of Helios" or "star of Sol" was applied to Saturn.5"[16] Where 5 is Bouche-Leclerq, L'Astrologie Grecque, 93, note 2.

"Though the Greek Kronos was the Latin Saturn, Nonnus gives Kronos as the Arab name of the "sun.""[16]

"Hyginus, in listing the planets, names first Jupiter, then the planet "of Sol, others say of Saturn."6 Why was the planet most distant from the sun called both "sun" and "Saturn"?"[16]

Helios and El[edit]

The "Greek name Helios so closely resembles the Greek transliteration of the Phoenician El that classical authors confused the two gods; since El is the Greek Kronos--and is so translated by Philo--Kronos/Saturn came to be confused with Helios, the sun.7 Yet, as noted by Boll, the identification is more wide-spread than generally acknowledged and is much more than a misunderstanding of names.8"[16]

Helios and Kronos[edit]

"In the Epinomis of Plato (who lived in the fifth and fourth centuries B.C.), there is an enumeration of the planets, which as customarily translated, entails this unstartling statemnet: "There remain, then, three stars (planets), one of which is preeminent among them for slowness, and some call him after Kronos."9 Yet the original reading is not Kronos but Helios10--which is to say that Plato (or his pupil Phillip of Opus, to whom some ascribe authorship of the Epinomis) gave the name Helios to Saturn. But copyists, who could not believe that Helios was anything other than the sun, "corrected" the reading to "Kronos." Moreover, writes Boll, this practice of "correcting" the name Helios to Kronos was not uncommon among later copyists.11 Originally, Boll concludes, Helios and Saturn were "one and the same god."12"[16]

Shamash and Saturn[edit]

"Of the Babylonian star-worshipers the chronicler Diodorus writes: "To the one we call Saturn they give a special name, 'Sun-Star'."13 Among the Babylonians the "sun"-god par excellence was Shamash, the "light of the gods," whom scholars uniformly identify with the solar orb."[16]

In the Babylonian astronomical texts the identification of Shamash with Saturn is unequivocal: "the planet Saturn is Shamash" they boldly declare.[18]

In support of this numerous examples are cited involving "the interchangeable application of the term 'Šamaš' to either the great orb of the day or the planet Saturn."[18]


"The apparent equivalence of Saturn and the "sun" goes back to Sumerian times, as is evident in the dual aspect of the creator god Ninurta."[16]

"Langdon deems Ninurta both the sun and saturn: "... the sun-god Ninurta ... in the original Sumerian Epic of Creation, defeated the dragon of chaos and founded cities ... In Sumero-Babylonian religion he is the War-god and planet Saturn."16"[16]

"It is not difficult to see why Ninurta, or Ningirsu, though identified with the planet Saturn in the astronomical tests, came to be confused with the solar orb."[16]

"Ningirsu, coming from Eridu, rose in overwhelming splendour. In the land it became day."[19]

"Saturn, as Ningirsu, is "the god who changes darkness into light."[20]

"The priests of Lagash invoke him as "King, Storm, whose splendour is heroic."[21]"[16]

Setting of the solar orb[edit]

"Considerable evidence suggests that, to the ancients, the day began with [...] the setting of the solar orb. It is widely acknowledged that the Egyptian day once began at sunset.25"[16]

"The same is true of the Babylonians and Western Semitic days.26"[16]

"The Athenians computed the space of a day from sunset to sunset, and the habit appears to have prevailed among northern European peoples.27"[16]

"Saturn "came forth in over-whelming splendour. In the land it became day."28"[16]

"So long as the solar orb was visible, the fiery globe of Saturn remained subdued, unable to compete with the sheer light of the former body. But once the solar orb sank beneath the horizon, Saturn and its circle of secondary lights acquired a terrifying radiance."[16]

Center of the Cosmos[edit]

"The Greek sun-god Helios, in an old tradition, resides at the center of the Cosmos, with the heavenly bodies revolving around him.108"[16]

"Upon evaluating the imagery of Helios in Homer's Odyssey, Butterworth concludes that the mythical sun remained always at the zenith, the celestial pole.109"[16]


  1. Helios was an early name for Saturn, or a former Saturn entity.

See also[edit]


  1. "heliology". San Francisco, California: Wikimedia Foundation, Inc. 2 June 2014. Retrieved 2014-08-02.
  2. "Sun". San Francisco, California: Wikimedia Foundation, Inc. 21 June 2014. Retrieved 2014-08-02.
  3. The Illustrated Oxford Dictionary, Oxford University Press, 1998
  4. "the sun". San Francisco, California: Wikimedia Foundation, Inc. 21 June 2014. Retrieved 2014-08-02.
  5. 5.0 5.1 S.G. Djorgovski; et al. "A Tour of the Radio Universe". National Radio Astronomy Observatory. Retrieved 2014-03-16. Explicit use of et al. in: |author= (help)
  6. O. Manuel, C. Bolon, A. Katragada, and M. Insall (2001). "Attraction and Repulsion of Nucleons: Sources of Stellar Energy". Journal of Fusion Energy. 19 (1): 93–8. doi:10.1023/A:1012290028638. Retrieved 2014-04-13.CS1 maint: multiple names: authors list (link)
  7. David R. Williams (September 2004). "Sun Fact Sheet". Greenbelt, MD: NASA Goddard Space Flight Center. Retrieved 2011-12-20.
  8. M. Asplund, N. Grevesse and A. J. Sauval (2006). "The new solar abundances - Part I: the observations". Communications in Asteroseismology. 147 (01): 76–9. Bibcode:2006CoAst.147...76A. doi:10.1553/cia147s76. Retrieved 2013-08-08. Unknown parameter |month= ignored (help)
  9. William J. Chaplin, Aldo M. Serenelli, Sarbani Basu, Yvonne Elsworth, Roger New, and Graham A. Verner (2007). "Solar Heavy-Element Abundance: Constraints from Frequency Separation Ratios of Low-Degree p-Modes". The Astrophysical Journal. 670 (1): 872–84. arXiv:0705.3154. Bibcode:2007ApJ...670..872C. doi:10.1086/522578. Retrieved 2013-08-08. Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  10. "Uranus, In: Wikipedia". San Francisco, California: Wikimedia Foundation, Inc. December 18, 2012. Retrieved 2012-12-23.
  11. A. Bonanno, H. Schlattl, L. Paternò (2008). "The age of the Sun and the relativistic corrections in the EOS". Astronomy and Astrophysics. 390 (3): 1115–1118. arXiv:astro-ph/0204331. Bibcode:2002A&A...390.1115B. doi:10.1051/0004-6361:20020749.CS1 maint: multiple names: authors list (link)
  12. David F. Gray (1992). "The Inferred Color Index of the Sun". Publications of the Astronomical Society of the Pacific. 104 (681): 1035–8. Bibcode:1992PASP..104.1035G. Unknown parameter |month= ignored (help)
  13. Samantha Harvey (April 26, 2007). "Solar System Exploration". Washington, DC USA: National Aeronautics and Space Administration. Retrieved 2013-08-08.
  14. 14.0 14.1 Reuven Ramaty, Vincent Tatischeff, J. P. Thibaud, Benzion Kozlovsky, and Natalie Mandzhavidze (2000). "6Li from Solar Flares". The Astrophysical Journal. 534 (2): L207-10. arXiv:astro-ph/0003356. Bibcode:2000ApJ...534L.207R. doi:10.1086/312671. Retrieved 2014-04-08. Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  15. CK Birdsall, A. Bruce Langdon (October 1, 2004). Plasma Physics via Computer Simulation. New York: CRC Press. p. 479. ISBN 0-750-3-1035-1 Check |isbn= value: checksum (help). Retrieved 2011-12-17.
  16. 16.00 16.01 16.02 16.03 16.04 16.05 16.06 16.07 16.08 16.09 16.10 16.11 16.12 16.13 16.14 16.15 16.16 16.17 David N. Talbott (1980). The Saturn Myth. Garden City, New York, USA: Knopf Doubleday & Company, Inc. p. 419. ISBN 0-385-11376-5. Retrieved 2013-01-03.
  17. Franz Boll (1916–19). "Kronos-Helios". Archiv für Religionswissenschaft. XIX. |access-date= requires |url= (help)CS1 maint: date format (link)
  18. 18.0 18.1 M. Jastrow (1909). "Sun and Saturn". Revue d'Assyriologie et d'Archéologie Orientale. 7: 163–78. |access-date= requires |url= (help)
  19. W. F. Albright. "The Mouth of the Rivers". The American Journal of Semitic Languages and Literatures. XXXV (4): 165. |access-date= requires |url= (help)
  20. Morris Jastrow, Jr. (June 1898). The Religion of Babylonia and Assyria. Boston: Ginn and Company. p. 780. Retrieved 12 October 2018.
  21. Hildegard Lewy (1 November 1950). "Origin and Significance of the Mâgen Drâwîd". Archív Orientální. 18 (3): 330–365. Retrieved 12 October 2018.

Further reading[edit]

External links[edit]

{{Chemistry resources}}{{Radiation astronomy resources}}