The sun has gone out

That's overly dramatic, but the thing that no one is saying is that it's entirely possible that after burning furiously for the last century the sun may have exhausted the fuel closest to the core, and as a result the rate of fusion has slowed.

So is it doomsday?

Not quite. There's still a lot of fuel there, but the sun is a really large object and it may take some time for more fuel to fall inwards to the center of gravity.

I'm no physicist but I've heard this theory before as sort of a "fringe" thing mumbled in science fiction backwaters. The upshot is that it could get pretty cold, so buy some long johns.

What's wrong with the sun? - space - 14 June 2010 - New Scientist

Sunspots are windows into the sun's magnetic soul. They form where giant loops of magnetism, generated deep inside the sun, well up and burst through the surface, leading to a localised drop in temperature which we see as a dark patch. Any changes in sunspot numbers reflect changes inside the sun. "During this transition, the sun is giving us a real glimpse into its interior," says Hathaway.

When sunspot numbers drop at the end of each 11-year cycle, solar storms die down and all becomes much calmer. This "solar minimum" doesn't last long. Within a year, the spots and storms begin to build towards a new crescendo, the next solar maximum.

What's special about this latest dip is that the sun is having trouble starting the next solar cycle. The sun began to calm down in late 2007, so no one expected many sunspots in 2008. But computer models predicted that when the spots did return, they would do so in force. Hathaway was reported as thinking the next solar cycle would be a "doozy": more sunspots, more solar storms and more energy blasted into space. Others predicted that it would be the most active solar cycle on record. The trouble was, no one told the sun.