I don't wish to alarm you, but the sun is supposed to be covered with spots right now -- according to solar-cycle charts, this should be an active year for sunspots -- and instead is eerily clean. "Blank," in space-weather lingo. Here, you can click on "latest Mauna Loa image" to see how the surface of the sun looked on Monday; additional daily solar images are here. In March 2006, the National Center for Atmospheric Research predicted the next solar cycle would begin no later than 2008, and that by 2009, much of Sol's surface would be sunspots. Also in 2006, NASA's David Hathaway, a prominent solar physicist, predicted a "ferocious" sunspot cycle happening around now. Power and communications companies were advised to expect substantial disruption from solar storms -- the nascent cell-phone business has not yet coped with a solar maximum. Instead all is quiet on the surface of the sun.
Sunspot cycles are thought to be caused by rhythmically changing currents in the sun's magnetic fields, but that's only the leading guess. Though human life depends on the sun, NASA has spent just a tiny fraction of its resources studying our star -- plunking a Motel 6 on the moon obviously is far more important! Astronomers have known of sunspots since ancient times, but detailed observations date only to 1755, and the concept of the solar cycle was not proposed until 1843, by the astronomer Samuel Schwabe. Solar luminosity is thought to decline slightly when sunspots are absent -- during the "Maunder Minimum" and then "Dalton Minimum," periods covering much of 1650 to 1850, sunspot activity was below average and Europe had cold winters followed by late springs. Professional doomsayer Al Gore endlessly declares that the last two decades have been "the warmest on record" -- he doesn't add that the "record" of reliable temperature data begins in the late 19th century, just when prolonged solar minima were ending and Earth entered a period of recovery from cool centuries. (Meaning temperatures likely would have risen in the 20th century whether man existed or not; I believe greenhouse gases should be regulated, it's just that it would be nice if Gore were honest about the evidence.) Lack of current sunspot activity may help explain why, though all computer models predict increasing artificial global warming, the last couple of years have been slightly cool. (Slightly cool years do not disprove global warming.)
Cosmologists are in broad agreement that Sol is a "main sequence" star which should continue to burn at uniform power for at least several hundred million years; other stars similar to Sol appear to burn uniformly for very long periods. Stars like the sun aren't supposed to change output over time horizons that matter to people, though do gradually become warmer, as gravity compresses them. A core mystery of climate is why, though the sun has been growing moderately warmer for perhaps a billion years, past epochs were much hotter than today -- when the dinosaurs lived, Antarctica was forested -- while the past 40 million years have been characterized by cyclical ice ages. There is no scientific consensus on the cause of geologically "recent" ice ages. But they shouldn't be happening, at least for solar reasons, if the sun is gradually warming as cosmologists believe.
Why did The Experts forecast a ferocious sunspot cycle only to observe, so far, quietude? Lack of knowledge of the sun is surely the primary explanation. The secondary explanation might be desire to get media attention by predicting something that sounds like a made-for-TV sci-fi movie. Then again, maybe the sun is about to fail.
The sun has probably gone through countless periods of surface quietude in the past, and we are only now noticing. Here's what to lose sleep over. Standard solar models predict the sun should be producing huge numbers of neutrinos, but elaborate, expensive attempts to detect neutrinos streaming from the sun don't find them. Standard solar models further predict a star like Sol would stop producing neutrinos when it is about to fail. Theory says the sun should be producing lots of sunspots and lots of neutrinos. It's making neither. A new concept says "neutrino oscillation" may account for why neutrinos could be absent but the sun remains fine. Let's hope this concept is right.
The late sci-fi writer Arthur Clarke's "The Songs of Distant Earth," published in 1986, concerns what would happen if the sun is about to die. In the book, early in the 21st century it is realized that Sol is failing and will go supernova relatively quickly in cosmic terms. (A physicist by training, Clarke was much more concerned with neutrino absence than sunspots.) In the novel, determined attempts to discover warp drive produce nothing. The only idea anyone can come up with to preserve life is to build cargo vessels bearing robots, supplies, seeds and human and mammal embryos, then send the vessels on lengthy journeys at a fraction of the speed of light. When the vessels arrive at a habitable world, the robots would go down to build shelters and plant crops; once it was safe, the embryos would be allowed to develop, tended by robots until new generations began.
In "The Songs of Distant Earth," for several centuries humanity devotes itself to launching gigantic cargo vessels packed with thousands of tons of robots, supplies, medical equipment and records of Earth, then dispatching them one by one toward distant star systems. At last, a sort of unplanned Golden Age occurs -- nations no longer fight, rather, concentrate their efforts on cooperation to spread life elsewhere. As expansion of the sun approaches, people stop having children, and Earth's population declines dramatically. Then a few years before the expected calamity, stardrive finally is invented -- and all energy is focused on construction of a magnificent starship to hold the final million people in suspended animation for a journey of 10,000 years to a world that resembles Earth. As human beings leave their cradle for the last time, the ship travels into a galaxy where many planets now have Earth-based life, spread by the robot vessels. The ship stops along the way to see what worlds might be like with transplanted humanity, but none of humanity's historical disputes and hatreds. "The Songs of Distant Earth" is a fun book -- read it to keep your mind off the possibility the sun is failing.