Could Sun go into 'hibernation' without warning?
What's the story
The Sun is currently in an 11-year solar maximum phase, but it also goes through minimum phases during its life cycle. From 1645 to 1715, the Sun experienced a grand solar minimum, or Maunder minimum, named after English astronomer Edward Walter Maunder who discovered this period. Now, scientists from Nagoya University in Japan have found a way to access data that could explain this solar dimming event.
Historical data
Mapping sunspots
German astronomer Johannes Kepler observed sunspots in 1607 using a camera obscura. His observations, captured by the pinhole camera, are the oldest known scientific depiction of a sunspot. Researchers have mapped these spots using Sporer's Law, which tracks how sunspots move from the poles to the equator over an 11-year cycle. This data suggests that in 1607, the Sun was nearing the end of its solar cycle.
Cycle analysis
Study of Kepler's data
The study of Kepler's data is crucial to understanding the Maunder minimum. It helps determine if the solar cycles before this period were normal or had signs indicating an impending "shutdown." The findings indicate that the cycle ending around 1607 was of regular length, suggesting no major changes in solar behavior during this time.
Research findings
Insights into grand solar minimum
The study offers valuable insights into the "warning signs" of a grand solar minimum. It confirms that the Sun behaved normally just before entering the Maunder Minimum, showing these deep solar hibernations can occur without significant long-term changes in cycle duration. "By situating Kepler's findings within broader solar activity reconstructions, scientists gain crucial context for interpreting changes in solar behavior, marking a transition from regular solar cycles to grand solar minimum," said Hisashi Hayakawa, lead author of the study.