The Sun does have an orbit. It orbits the centre of mass of the solar system, as shown in the graphic above from Wikipedia, in response to the motions of the four giant planets, mainly those of Jupiter and Saturn but with additional effects from Uranus and Neptune.

The apparent rule is that the Sun never crosses its own path of motion during a single solar cycle, defined as the period from minimum to minimum of sunspot (magnetic) activity, normally in the 9-13 year range.

The question is: why does this happen?

Graphic notes:
Colour changes every decade: 1950/60/70/80/90.
Each black spot is +1 year along the coloured line.
Black square indicates start/end of a solar cycle [Talkshop addition to the original graphic].

START DATES
SC18 = 1944 – Feb
SC19 = 1954 – Apr
SC20 = 1964 – Oct
SC21 = 1976 – Mar
SC22 = 1986 – Sep

Dates from List of solar cycles – Wikipedia.

The ‘rule’ holds right back to solar cycle 5, based on the Solar Simulator app of Carsten Arnholm, and for SC 1,2 and 3.

However, in Solar Cycle 4 the Sun does overshoot its current solar cycle orbit briefly near its end, but this cycle is sometimes described as anomalous, being unusually long at 13.7 years. Some theorists even say it could be two cycles, or one plus a ‘failed’ one, as it’s said to have only one peak. The anomaly question is unresolved.
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Image: solar motion relative to the solar system barycentre [original source here].

via Tallbloke’s Talkshop

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January 5, 2025 at 07:00AM