NASA and NOAA have confirmed that the Sun has entered a new solar cycle, with activity beginning to ramp back up from its minimum in December 2019. This next cycle is forecast to be rather quiet, continuing a long-term trend of reduced activity from our parent star.
The Sun goes through phases like clockwork, marked by periods of heightened and reduced activity. Each of these solar cycles lasts 11 years, as measured from one so-called solar minimum through a solar maximum and back down to the next minimum.
In a press conference this week, NASA and NOAA confirmed the beginning of a new solar cycle, after the last solar minimum was observed in December last year. While this may seem like a late announcement, these things can really only be declared after the fact, when enough data has been gathered.
The ebb and flow of the Sun’s activity is calculated through the number and size of sunspots. These dark splotches on the surface of the Sun are areas of relatively lower temperatures and higher magnetism, which produces more flares and coronal mass ejections.
“We keep a detailed record of the few tiny sunspots that mark the onset and rise of the new cycle,” says Frédéric Clette, director of the World Data Center for the Sunspot Index and Long-Term Solar Observations. “These are the diminutive heralds of future giant solar fireworks. It is only by tracking the general trend over many months that we can determine the tipping point between two cycles.”
Looking ahead, the team says that Solar Cycle 25 will reach its next maximum around July 2025, and head back to a minimum in about 2030. It’s also likely to be a fairly quiet cycle in the grand scheme of things, on the scale of the previous cycle or possibly even quieter.
Solar Cycle 24, which started in December 2008, was the weakest solar cycle in about a century. Although the Sun definitely had its active moments, overall the number of sunspots was far lower than average, even during solar maximum in April 2014. That led some scientists to speculate that we're in a “Grand Minimum,” a period of exceptionally reduced activity guided by some unknown longer-term cycle.
On the plus side, less solar activity means fairer space weather ahead for astronauts, satellites and other spacecraft. Still, it pays to be prepared for all eventualities, and even a quiet Sun can still throw out some curveballs.
“Just because it’s a below-average solar cycle, doesn’t mean there is no risk of extreme space weather,” says Doug Biesecker, panel co-chair at the Space Weather Prediction Center (SWPC). “The Sun’s impact on our daily lives is real and is there. SWPC is staffed 24/7, 365 days a year because the Sun is always capable of giving us something to forecast.”
Source: NASA