Quiet SunNovember 8th, 2012 at 8:17 pm by Bill Steffen under Bill's Blog, Weather
Click on the image or click here to enlarge. The number of sunspots has been unusually low over the last decade. You can see that the number of sunspots is well below the predicted number. The 11-year sunspot cycle has been forecast to peak around March 2013, but in recent weeks, there has been speculation that we may being seeing the peak here in late 2012. This is the quietest sun in at least a century. There have been other solar factors that have been interesting. The solar wind has dropped to a historic low. The article at the link also says: “In addition to weakened solar wind, the spacecraft Ulysses also finds that the sun’s underlying magnetic field has weakened by more than 30% since the mid-1990s”. We are at a record low for solar radio emission (since measurements began just prior to WWII). We also have a downturn in solar irradiance, down .02% in the visible spectrum, but a full 6% in the extreme UV spectrum since the mid 1990s. There has been some speculation about whether this downward trend of solar activity is the start of a longer period of quiet solar activity, similar to the Maunder Minimum, which coincided with a significant cooling of the Earth. The Dalton Minimum and Spörer Minimum, also coincided with a period of lower-than-average global temperatures. This from NASA: “The longest minimum on record, the Maunder Minimum of 1645-1715, lasted an incredible 70 years. Sunspots were rarely observed and the solar cycle seemed to have broken down completely. The period of quiet coincided with the Little Ice Age, a series of extraordinarily bitter winters in Earth’s northern hemisphere. Many researchers are convinced that low solar activity, acting in concert with increased volcanism and possible changes in ocean current patterns, played a role in that 17th century cooling. For reasons no one understands, the sunspot cycle revived itself in the early 18th century and has carried on since with the familiar 11-year period. Because solar physicists do not understand what triggered the Maunder Minimum or exactly how it influenced Earth’s climate, they are always on the look-out for signs that it might be happening again.
The low solar activity has also caused a decrease in the number of days when we have a spectacular view of the auroras.
Also, there is a solar eclipse next Wednesday. You won’t see it here, but they’ll get a nice view in Northeast Australia. And you can check out the video of an M-Class flare that occurred Thursday morning. At the last link you’ll also see a picture of a fireball that flew across Mexico that was much brighter than the full moon. There’s some neat pictures of the Northern Lights here. You can check out This Week’s Sky at a Glance and here’s a list of flyovers of the International Space Station. There’s a couple of good ones early Weds. and Fri. of next week.