Sunday, September 28, 2008
Jimmy Westlake's Celestial News column appears Tuesdays in the Steamboat Today.
Find more columns by Westlake here.
There are few things in our lives that seem as constant and dependable as the sun. Day after day, it provides the warmth and energy that we must have to survive on this planet. Without it, Earth would be in an unimaginable deep freeze near absolute zero.
So, it comes as a bit of surprise when we learn the sun is misbehaving a bit and not following its usual routine. The routine is this: Every 11 years, the number of sunspots and other active regions on the sun reach a frenzy of activity, followed by a period of relative calm. Like a heartbeat of cosmic proportions, this 11-year rise and fall in solar activity has gone on for decades, even centuries, with few interruptions. The last solar maximum occurred between the years 2001 and 2002, when giant sunspots and record-breaking solar flares erupted into space. Clouds of charged particles from the sun generated brilliant displays of the Northern Lights over Colorado and points even farther south. Since then, solar activity has waned, as expected when nearing the end of a solar cycle and another solar minimum.
The problem is that this solar minimum is lasting for an uncomfortably long time. The average solar cycle lasts for 131 months, or about 10.9 years. The current cycle already has lasted 144 months (12 years) and we are still counting. Sunspots during the last two years have been scarcer than hen's teeth, and the few that have appeared have been tiny and short-lived. Every morning, I check out the daily image of the sun on www.spaceweather.com and scan for sunspots, but every day it's the same story: "The sun is blank today - zero sunspots." The last time the sunspot cycle went into extended hibernation was during the so-called Maunder Minimum between the years 1645 and 1715. This period coincided with Europe's "Little Ice Age," one of the most dramatic episodes of global cooling in recorded history.
While the sunspot-climate connection is poorly understood, there is little doubt that it exists. In many places around the world, including Colorado, the winter of 2007-08 was a record-setting year of cold temperatures and snowfall. Average global temperatures took their largest single-year decrease in years, and NASA has predicted that the coming decades will see much colder global temperatures. To top it all off, this week NASA announced that satellite measurements of the solar wind indicate a 50-year low in the flow of charged particles from our local star (http://science.nasa.gov/headlines/y2008/23sep_solarwind.htm).
What does all this mean? No one knows for sure, because this low level of solar activity is unprecedented since the space age began. All we can do is sit back and watch for the sunspots to return and thrown another log on the fire for what is expected to be another very cold winter.
Professor Jimmy Westlake teaches astronomy and physics at Colorado Mountain College's Alpine Campus. He is an avid astronomer whose photographs and articles have been published on the Web sites of CNN.com, NASA's "Astronomy Picture of the Day" Web site, Spaceweather.com, Space.com, Discover.com, MSNBC.com, NationalGeographic.com, and in Sky & Telescope, Astronomy, Night Sky, Discover, and WeatherWise magazines. His "Celestial News" article appears weekly in the Steamboat Pilot & Today. His "Cosmic Moment" radio spots can be heard on local radio station KFMU. Check out his Web site at www.jwestlake.com.