Mike Wall, SPACE.com Published: Mar 7, 2013, 2:37 PM EST From our partners
The image above shows the Earth-facing surface of the Sun on February 28, 2013, as observed by the Helioseismic and Magnetic Imager (HMI) on NASA’s Solar Dynamics Observatory.
The sun is surprisingly quiet at the moment, but that may be because our star is gearing up for the second phase of a one-two wallop in its 11-year activity cycle, some scientists say.
The sun has slumped to its present lull from a very fiery 2011, seeming to contradict a widely predicted 2013 peak in solar flares, sunspots and other activity for the current Solar Cycle 24. But the forecasts may be right after all, said solar physicist Dean Pesnell, of NASA’s Goddard Space Flight Center in Greenbelt, Md.
“This is solar maximum,” Pesnell, project scientist for NASA’s Solar Dynamics Observatory spacecraft, said in a statement. “But it looks different from what we expected because it is double-peaked.”
This Storm Would Burn Earth
Though the sun’s activity cycle is often regarded as a smooth bell curve, proceeding from low to high and then back down to low again, twin peaks are apparently not too uncommon. The last two solar maxima — which occurred in 1989 and 2001 — were doubled-peaked, exhibiting mini-cycles that lasted about two years, Pesnell added.
So the 2011 surge may just have been part one of Solar Cycle 24’s fireworks display.