What does 10 years mean to our 4.6 billion-year-old sun? Probably about as much as the last millionth of a second meant to you. Still, every decade that our old sun burns on is a decade of turbulent, sometimes violent change — a fact that becomes beautifully evident in a new time-lapse video from NASA’s Solar Dynamics Observatory (SDO).
In the stunning video, titled “A Decade of Sun,” astronomers compiled 425 million high-definition images of the sun, snapped once every 0.75 seconds between June 2, 2010 and June 1, 2020. Each second of the video represents one day in the sun’s life, and the entire decade blazes by in about 60 minutes (though you can see our 6-minute highlight reel above).
During that decade, the sun undergoes a sea change, slowly bubbling with enormous magnetic ripples known as sunspots, which peaked around 2014 before fading away again. The sun’s quiescence wasn’t a surprise; every 11 years or so, the sun’s magnetic poles suddenly switch places; North becomes South, solar magnetic activity begins to wane, and the sun’s surface starts to look like a tranquil sea of yellow fire. This period of relative calm is called a solar minimum (and we are currently in the midst of one).
Halfway between one decade’s flip-flop and the next, however, a violent shift occurs. Magnetic activity increases to a vibrant high, known as a solar maximum, and the star’s surface ripples with gigantic sunspots, bristles with lashing magnetic field lines and pops with plasma explosions known as solar flares. Each maximum peaks with another magnetic pole reversal, signaling the start of a new solar cycle.
These changes are hard to spot from Earth with the naked eye (though solar maxima do result in more visible auroras at lower latitudes around the world), but NASA’s SDO satellite sees them clearly as it monitors our star in extreme ultraviolet light. These ultra-energetic wavelengths cut through the sun’s glare and reveal the abundant magnetic changes in the sun’s outermost atmosphere, or corona. It’s a stunning spectacle to see — even if the sun has probably already forgotten all about it.
Sourse: www.livescience.com
