Solar activity - Introduction

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Periodical changes

Observations of the Sun

Thomas Harriot (1610), Galileo Galilei, Johan Fabricus (1611), Christoph Scheiner (1611-1633),
Johannes Baptista Cysat, Jean Tarde (1615-1619), Charles Malapert (1618-1626), Danie Mogling (1626-1629),
Pierre Gassendi (1631-1646), Johannes Hevelius (1652-1685), Jean Picard (1650-1685), Robert Boyle (1661),
Phillipe La Hire(1700-1718), Francois de Plantade (1704-1726), Christian Horrebow (1761-1776), Alexander Wilson (1774),
William Herschel (1800-1826), Samuel Heinrich Schwabe (1826-1868), Rudolf Wolf (1847-1893), ...
Ma Tuan Siena (Čína, 301-1205), Hiraiama (Tokio,188-1638)

Motion of the Sun

According to Newton Earth (E) does not move around the Sun (C=centre), but both bodies orbit their gravity centre G(C,E). The same holds also for Earth and Moon (L=lunar), Moreover it is not the Earth, but G(E,L) what moves around G(C,E)... Considering more planets, all becomes more complicated:

Sun makes composite motion as response to motion of planets.

Providing that there are no unknown planets, progress of the Sun is caused mainly by planets Jupiter and Saturn. Barycentre i.e. gravity centre G(C,planets), moves either inside of the Sun (c. 36% of time) or it does not depart too far from margin of the Sun. Near conjunction J-S the barycentre achieve distance from the Sun c. 2.2 RS (RS is radius of the Sun).

Sun defend against motion forced by motion of planets. And its retroactive action on planets can cause certain synchronization of motion of all bodies (planets).

Distance Sun-barycentre

a 108 [km]

M/ mi [10³]

Di [km]

















Distance of Sun from barycentre

Distance D of Sun from barycentre is caused mostly by outer planets (J,S,N,U), other known bodies have imperceptible influence.

Departure influenced by Jupiter (742792 km) is the only one, that stick center of gravity out of the Sun (Rs~696000 km).

Total distance of the centre of gravity is D=∑Di, where Di = ai * mi/M and ai is distance of planet from the Sun, mi mass of the planet and M total mass. Mass of the Sun MSUN~1990.00 [1027kg], mass of all planets ∑mi ~2.67 [1027kg]. Because ∑mi is small with regard to MSUN, mass of whole system M~MSUN.

Speed and acceleration of the Sun

Year L v w --------------------------------------------------- 1994 79,65 89,2 199,9 1995 97,41 98,1 244,2 1996 115,96 108,5 284,1 1997 135,39 118,2 265,7 1998 155,96 127,2 245,5 1999 177,77 133,0 160,7 2000 201,10 135,7 73,7 2001 226,33 134,3 -39,9 2002 254,15 129,8 -122,4 2003 285,40 123,5 -172,7 2004 319,91 116,4 -193,8 2005 355,66 110,1 -173,5 2006 29,43 104,2 -160,4 2007 60,11 100,1 -112,8 2008 88,17 96,6 -96,2 Speed (v) and acceleration (w) of the Sun markedly changes. Main period of changes came from (J,S) ~19.86 years.

Similarly as (for the reason of elliptical orbits) distances of conjunctions J-S changes: 1940.85 ( 20.41) 1961.26 ( 20.01) 1981.28 ( 19.15) 2000 also distances of highest accelerations 1938 (18) 1956 (20) 1976 (20) 1996 and highest decelerations 1947 (20) 1967 (22) 1989 (15) 2004 of the Sun (with regard to barycentre) changes.

    Year   L        v         w
    1938   150,5    115,8     251,3
    1947     7,0    105,1    -212,8
    1956   355,0    105,6     164,7
    1967   292,4    102,7    -224,1
    1976   233,9    105,0     211,0
    1989   160,9     92,7    -276,2
    1996   116,0    108,5     284,1
    2004   319,9    116,4    -193,8

In spite of variability in distance of extremes (c. 15-22 year), there is still period (J,S) ~19.86 years on the background.

Observation of acceleration of the Sun does not lead directly to cause of the primary 11-years cycle of solar activity.

For more on solar activity cycles see page Solar cycles.

Long-term changes

In the years 1810-1812 (Dalton minimum) was Jupiter in opposition to Saturn, Uranus and Neptune (J-SUN).
A similar such configuration of planets occurred for example in 1989-1991.

1.1.1811 s_longterm2 1.1.1990 s_longterm4

Other configurations (Dalton extremes) can be found in years (bold blue - minimum, bold red - maximum):
84-85, 124-126, 263-265, 303-304,442-444, 483, 621-623, 762, 800-801,
1134, 1314, 1492, 1631, 1671, 1810-1812, 1850, 1989-1991, 2029-2030, 2168-2170.

If the opposition J-SUN implies a minimum of solar activity, then it is necessary to explain the increase of activity in years 1134 (the medieval maximum) and 1989-1991 (the modern maximum).

s_longterm6 (graph – geomagnetic index - prof.Silvia Duhau).

Theory of solar activity

The influence of planets on solar activity

1/ Theory of Jupiter influence

2/ Tidal theory

3/ Theory of angular momentum changes

a/ Angular momentum

Some theories derive solar activity from changes of angular momentum of (outer) planets. Hereat maximal momentum is in time of conjunction of planets (barycentre is deflected to side of planets) , minimal momentum is in time of opposition (barycentre is near to the centre of the Sun).

In both these examples the change of momentum is minimal and therefore minimum activity is expected. Maximum activity has to be in time of angular distance of planets c. 60º, i.e. there are 2 maxima for 1 minimum!? According to these assumptions there would be minimum activity around year 1992 (this does not occurred).

b/ Quadratures

4/ Theory of barycentric location

a/ Barycentric deflection

c/ Barycentric direction

Theodor Landscheidt showed that higher activity on Sun is directed from and to barycentre.

A similar principle (in combination with tidal theory) introduced (independently from Landscheidt) geophysicist Pavel Kalenda.

5/ Resonance theory

Small (tidal) effects enhance the natural oscillation of the solar atmosphere and cause great changes.

Denial of the possible influence of planets

The existence of the solar dynamo (C.Jager, S.Duhau) or other internal periodic phenomena on the Sun is assumed. Research focuses on magnetic fields, solar plasma behavior, physical and statistical surveys, and the like.

Regarding reflection of conjunctional cycles, dependences on heliographic latitudes were observed (Václav Bumba)

Selected solar extremes

Selected solar maxima

Maximum y.1727

Locally higher solar maximum 1727 is connected to the opposition of Uranus against Jupiter (Neptune and Mars). Saturn and the Earth are found on perpendicular to this conjunction line. Opposition Jupiter-Uranus 1727.59.



Maximum y.1859
Carrington proton event - Solar superstorm.


syst 18590901
Aurora y.1862

The Civil War Aurora - Aurora Borealis - 14.10.1862

syst 18621014

2004 -2146 -2289

See also oppositions of Jupiter against inner planets (1288.2 - 1574.4 - 1860.6)
or conjunctions NX (1309 - 1595 - 1883).
Maximum y.1372

Highest Schove’s extreme of solar activity. Symmetric configurations of outer planets: JN-SU, y.1372.13 (JS-UN, y.1376.72, JU-SN, y.1377.14). Passage of all outer planets through perihelia J:1382.44, S:1384.55, U:1378.38, N:1387.45.



Selected solar minima

Minimum y.1257

There was (according to Schove) lower solar activity in time of conjunction of all outer planets (J-S-U-N) in year 1306 (and also 180 year later in 1485) . In book The Role of the Sun in Climatic Change (Douglas V.Hoyt, Kennet H.Schatten, 1997) authors note climatic anomalies around 1300 (with cross-reference to work of E.Huntington and S.S.Visher Climatic Changes: Their Nature and Causes, 1922).

After big drought in America (1276-1299) drought period in India and in basin of Nil followed around year 1300.

Baltic See froze in years 1296, 1306, 1323. In the year 1304 strong oceanic stormy waves are documented.

So the year 1306 seems to be reference point.

But cooling started already in years 1240-1260. Minimum (according to Schove) in weak phase of Solar cycle come in the year 1256. In the end of 1257 oppositions J-U and R-S synchronized (see above).



Minimum y.1810

The year 1810 is considered to be a point of synchronization – year without activity. In this year no solar flare was observed.

During break of years 1811/1812 there were three strong earthquakes in New Madrid (American state Missouri)



Distance of time-point 1810.50 from observed maximum of S-activity y.1958.8 makes c. 147.3 years, i.e. 5 period of Saturn (5*S=5*29.457 years = 147.286 years).

With the same period - conjunctions of Earth and Mars synchronize. Conjunction E-R appeared at the same time as Saturn passing through perihelion e.g. in years 1561.63, 1709.02, 1856.26 and 2003.66.