4 min read
It looked like the Sun was heading toward a historic lull in activity. That trend flipped in 2008, according to new research.
The Sun has become increasingly active since 2008, a new NASA study shows. Solar activity is known to fluctuate in cycles of 11 years, but there are longer-term variations that can last decades. Case in point: Since the 1980s, the amount of solar activity had been steadily decreasing all the way up to 2008, when solar activity was the weakest on record. At that point, scientists expected the Sun to be entering a period of historically low activity.
But then the Sun reversed course and started to become increasingly active, as documented in the study, which appears in The Astrophysical Journal Letters. It's a trend that researchers said could lead to an uptick in space weather events, such as solar storms, flares, and coronal mass ejections.
"All signs were pointing to the Sun going into a prolonged phase of low activity," said Jamie Jasinski of NASA's Jet Propulsion Laboratory in Southern California, lead author of the new study. "So it was a surprise to see that trend reversed. The Sun is slowly waking up."
The earliest recorded tracking of solar activity began in the early 1600s, when astronomers, including Galileo, counted sunspots and documented their changes. Sunspots are cooler, darker regions on the Sun's surface that are produced by a concentration of magnetic field lines. Areas with sunspots are often associated with higher solar activity, such as solar flares, which are intense bursts of radiation, and coronal mass ejections, which are huge bubbles of plasma that erupt from the Sun's surface and streak across the solar system.
NASA scientists track these space weather events because they can affect spacecraft, astronauts' safety, radio communications, GPS, and even power grids on Earth. Space weather predictions are critical for supporting the spacecraft and astronauts of NASA's Artemis campaign, as understanding the space environment is a vital part of mitigating astronaut exposure to space radiation.
Launching no earlier than Sept. 23, NASA's IMAP (Interstellar Mapping and Acceleration Probe) and Carruthers Geocorona Observatory missions, as well as the National Oceanic and Atmospheric Administration's SWFO-L1
