solar physics Solar physics is the branch of astrophysics that specializes in the study of the Sun. It intersects with many disciplines of pure physics and astrophysics. Because the Sun is uniquely situated for close-range observing (other stars cannot be re ...

, Spörer's law is an empirical law for the variation of heliographic latitudes at which solar

active region In solar physics and observation, an active region is a temporary feature in the Sun's atmosphere characterized by a strong and complex magnetic field. They are often associated with sunspots and are commonly the source of violent eruptions suc ...

s form during a

solar cycle The Solar cycle, also known as the solar magnetic activity cycle, sunspot cycle, or Schwabe cycle, is a periodic 11-year change in the Sun's activity measured in terms of Modern Maximum, variations in the number of observed sunspots on the Sun ...

. It was discovered by the English astronomer

Richard Christopher Carrington Richard Christopher Carrington (26 May 1826 – 27 November 1875) was an English astronomer whose 1859 astronomical observations demonstrated the existence of solar flares as well as suggesting their electrical influence upon the Earth and it ...

around 1861. Carrington's work was refined by the German astronomer

Gustav Spörer Friederich Wilhelm Gustav Spörer (23 October 1822 – 7 July 1895) 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 ...

. At the start of a solar cycle, active regions tend to appear around 30° to 45° latitude on the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

's surface. As the cycle progresses, they appear at lower and lower latitudes, until they average 15° at

solar maximum Solar maximum is the regular period of greatest solar activity during the Sun's 11-year solar cycle. During solar maximum, large numbers of sunspots appear, and the solar irradiance output grows by about 0.07%. On average, the solar cycle take ...

. The average latitude then continues to drift lower, down to about 7° and then while the old sunspot cycle fades, active regions of the new cycle start appearing at high latitudes.

References

Eponymous laws of physics Solar phenomena {{sun-stub

See also

References