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 variations in the number of observed sunspots on the Sun's surface.

The observed and predicted Solar Cycle is depicted in Sunspot Number in the top graph and F10.7cm Radio Flux in the bottom graph. The predicted progression for the current solar cycle (Cycle 25) is given by the magenta line, with associated uncertainties shown …

Solar cycles are nearly periodic 11-year changes in the Sun's activity that are based on the number of sunspots present on the Sun's surface. The first solar cycle conventionally is said to have started in 1755.

6 days ago · Each month the solar prediction is updated using historical and the latest month’s observed solar indices to provide estimates for the balance of the current solar cycle and the next.

Apr 3, 2025 · The solar cycle affects activity on the surface of the Sun, such as sunspots which are caused by the Sun's magnetic fields. As the magnetic fields change, so does the amount of activity on the Sun's surface.

The solar cycle is a roughly 11-year periodic change in the Sun's sunspot activity, measured by the variation in the number of sunspots observed. Humans used telescopes to observe sunspots and solar cycles as early as the 17th Century; however, NOAA and NASA satellites are now major ways scientists use to study the Sun.

The total number of sunspots has long been known to vary with an approximately 11-year repetition known as the solar cycle. The peak of sunspot activity is known as solar maximum and the lull is known as solar minimum. Solar cycles started being assigned consecutive numbers.

Oct 16, 2024 · For centuries, scientists have been counting sunspots to track this 11-year solar cycle, watching as the Sun transforms from a blank, spotless disk during solar minimum to one freckled with sunspots during solar maximum.

Mar 10, 2025 · NASA and NOAA track sunspots to determine, and predict, the progress of the solar cycle — and ultimately, solar activity. Solar minimum is characterized by a low number of sunspots, while solar maximum is marked by many sunspots.

Sunspots are dark, planet-sized regions that appear on the surface of the Sun. They are caused by twisting, chaotic magnetic fields from within the Sun’s convective zone. These powerful magnetic disturbances produce active regions on the Sun, which can often create solar flares and coronal mass ejections (CMEs).