The Sun Has Been Spotless for 28 Days Straight Despite New Solar Cycle

The sun has been spotless for 28 days straight, with a total of 184 days of 2020 now sunspot-free. This is one of the longest sunspot-free stretches in recent years. There was a 24-day stretch in August last year, which was followed by a 28-day stretch in October. In 2018 there was a three-week stretch, with no sunspots for 21 days in July.

The latest stretch comes as scientists announce the start of a new solar cycle. On Tuesday, researchers said Solar Cycle 25 had begun, marking an end of Solar Cycle 24 and the emergence from the solar minimum—the point in the sun's 11-year cycle where activity drops to its lowest point.

Sunspots are dark patches that appear on the surface of the sun produced by magnetic activity. They are cooler than other parts of the surface and are associated with events like solar flares. Activity on the sun's surface waxes and wanes over the course of its cycle, with activity peaking during the solar maximum and dropping during the solar minimum. These 11-year cycles are numbered—with the latest being Solar Cycle 25.

Moving into Solar Cycle 25 means the sun is moving towards the solar maximum, with activity on the sun's surface expected to slowly increase until a peak around July 2025. According to the National Oceanic and Atmospheric Administration's Space Weather Service, the solar minimum for Solar Cycle 24 took place in December 2019., which tracks the sun's activity, pointed to the long sunspot-free stretch in an update Friday. "If Solar Cycle 25 has begun, then why is the sun so quiet?" it said. "The solar disk has been blank—zero sunspots—for 28 straight days. It only seems strange. The early months of new solar cycles are often interrupted by quiet spells, sometimes long ones. Solar Minimum doesn't give up easily. Eventually, though, it will give up."

The last solar cycle was unusually quiet, the NOAA said in a statement announcing Solar Cycle 25. "[It] had the 4th-smallest intensity since regular record keeping began with Solar Cycle 1 in 1755. It was also the weakest cycle in 100 years. Solar maximum occurred in April 2014 with sunspots peaking at 114 for the solar cycle, well below average, which is 179."

Some scientists have suggested we may be entering a "deep solar minimum" where activity on the sun drops below average cycle levels. It had also been suggested the sun could be headed towards a Grand Minimum, which is part of a longer-term variation in solar activity. The last Grand Minimum was in the 17th century and coincided with a mini ice age, although a link between the two events has not been confirmed.

Solar Cycle 25 is predicted to be very similar to the previous cycle. Researchers believe the latest cycle will mark the end of a longer trend where magnetic fields at the sun's poles were weakening. Lisa Upton, co-chair of the Solar Cycle 25 Prediction Panel, said there is "no indication" we are approaching a Grand Minimum.

solar minimum
The sun on December 15, 2019, during the solar minimum. Scientists have now announced Solar Cycle 25 has begun. NOAA