The solar minimum occurs approximately every 11 years when fewer sunspots like these appear.
Credit: NASA/Goddard Space Flight Centre
WASHINGTON: For years, scientists have been predicting the Sun would by around 2012 move into solar maximum, a period of intense flares and sunspot activity, but lately a curious calm has suggested quite the opposite.
According to three studies released this week, experts believe the familiar sunspot cycle may be shutting down and heading toward a pattern of inactivity unseen since the 17th century.
The signs include a missing jet stream, fading spots, and slower activity near the poles, said experts from the National Solar Observatory and Air Force Research Laboratory.
"This is highly unusual and unexpected," said Frank Hill, associate director of the NSO's Solar Synoptic Network, as the findings of the three studies were presented at the annual meeting of the American Astronomical Society's Solar Physics Division in Las Cruces, New Mexico.
"But the fact that three completely different views of the Sun point in the same direction is a powerful indicator that the sunspot cycle may be going into hibernation."
Last normal cycle for some time
Solar activity tends to rise and fall every 11 years or so. The solar maximum and solar minimum each mark about half the interval of the magnetic pole reversal on the Sun, which happens every 22 years.
Hill said the current cycle, number 24, "may be the last normal one for some time and the next one, cycle 25, may not happen for some time".
He added, "This is important because the solar cycle causes space weather which affects modern technology and may contribute to climate change."
Affecting climate, space exploration
Experts are now probing whether this period of inactivity could be a second Maunder Minimum, a 70-year period between 1645-1715, also known as the Little Ice Age, in which hardly any sunspots were observed.
"If we are right, this could be the last solar maximum we'll see for a few decades. That would affect everything from space exploration to Earth's climate," said Hill.
Solar flares and eruptions can send highly charged particles hurtling toward Earth and interfere with satellite communications, GPS systems and even airline controls.
