Thursday, 28 March 2013

When the Sun Takes a Vacation


Thursday, 28 March 2013

When the Sun Takes a Vacation

According to astronomers, the year 2013 may be an unlucky one, featuring solar flares that blast Earth with hot, ionized gas. Solar Cycle 24 is reaching its maximum, and our satellites and electrical grids are at risk! In the words of Sir John Beddington, the United Kingdom's chief scientific advisor, during a February 2011 meeting of the American Association for the  Advancement of Science, a sever storm could cause a "global Katrina" that would cost the word's economies as much as 52 trillion.
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Sound scary?

The only thing scarier than the Sun reaching the high peak of a cycle is when the Sun has a quiet cycle with almost no peak at all.

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According to some solar scientists, when the Sun last had a very quiet cycle, Earth experiences the "Little Ice Age" (A.D. 1550-1850). Some of these same scientists are warning that the current cycle's "peak" of activity is the weakest in 80 years. Even more alarming, several scientists report that this is a trend and that the next cycle (number 25, projected to begin in 2020 by David Hathaway, NASA's top solar storm scientist) may exhibit little to no solar activity at all.

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Following the sweltering temperatures of Summer 2011 and the early spring of 2012 and decades of warning about "global warming", a a cool spell may sound really refreshing. Yet warnings of a possible ice age are daunting. What are the scientists talking about?

The yellow ball in the sky is a busy, noisy place. The Sun is made of gas, and it rotates, generating a magnetic field--but various sections rotate differently. Its interior rotates much faster than its surface, and its equator rotates more quickly than its poles. Hot gases bubble and burst through the mix, tangling and looping the "lines" of the MAGNETIC FIELD. (See the effects and hear the Sun at Almanac.com/SunSounds.)

Sounds from these titanic explosions ripple through the Sun, disrupting gases and creating even more tangles. SUNSPOTS, which appear to us as dark patches, occur when these intense magnetic loops poke through the Sun's surface. Eventually, like an overstretched rubber band, each stressed magnetic field "breaks", releasing tremendous energy and spewing the magnetically charged gases into space. This explosion is called a SOLAR FLARE, and the hot spewed gases are called a CORONAL MASS EJECTION, or CME.

An increased number of of sunspots indicates an increased output of solar radiation. These tangles, tears, and explosions spray Earth with increased energy, from light and heat to X rays. Satellite readings show at the peak of a solar cycle, (when the most sunspots occur), the Sun emits the most radiation and energy.

Scientists have been counting sunspots and their cycles for centuries. They have also been able to reconstruct a record of solar activity for over 1,000 years by analyzing tree rings. Some of their discoveries are disturbing.

Even from the 9th to 13th (the Medieval Warm Period), the Sun was extremely active, with lots of sunspots and lots of radiation emitted toward Earth. Historical records show that Earth's climate was warm. Vikings grazed cattle on grasslands in Greenland and settled in Newfoundland.

Then the Sun entered a long quiet phase, during which the cycles were weak. Very few sunspots occurred (even maximum phases had minimal activity) and a lot less solar radiation reached Earth. Global temperatures dropped by 1.8ºF (1ºC).

This may not sound like much, but it produced effects that seem inconceivable today. In the 1600s, caravans of oxen carts with metal and hides departed from what is now Santa Fe, New Mexico, traveled 370 miles south; and then crossed over the frozen surface of the Rio Grande into what we know today as Mexico. From 1607 to 1814, citizens in England periodically held huge ice fairs on the frozen Thames Ricer. In 1780, it was so cold that people walked from Manhattan to Staten Island over the frozen New York Harbor.

The last drop in solar activity, which occurred from 1790 to 1830 (called the Dalton Minimum, for English meteorologist John Dalton, 1766-1844), was a time of crop failures, famines, and massive social turmoil.

It is important to note that daily, even year-to-year, variations of solar radiation have not produced noticeable changes in Earth's weather patterns. This is due, in part, to the oceans, which cover 70% of our planet. These bottles of water store enormous heat reserves and have significant influence on our weather (think El Niño conditions in a warm Pacific and hurricanes in a warm Atlantic). The oceans are slow to cool; most global cooling takes place over land, especially far inland from the coast.

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In June 2011, scientists from the National Solar Observatory warned that if then-current trends continued, the Sun's magnetic fields would be too weak to generate visible sunspots by 2022. In the words of Dr. Frank Hill, associate director of the National Solar Observatory's Solar Synoptic Network, "The solar cycle is maybe going into hiatus, sort of like [a t.v. show in summer]."
However, research by Danish scientists Eigil Friis-Christensen and Knud Lassen has shown that global temperatures do drop during quiet (inactive) sunspot cycles. Historically, during 11-year sunspot cycles of low activity and radiation, Earth Earth experienced cooler temperatures and, when the quiet period was prolonged over several cycles, "little ice ages". Think of it this way: If the globe were to cool 1ºF, the freeze zone would move roughly 350 miles south from its current position. (In Canada, where this would be referred to in metric measures, it sounds even more spectacular. If the globe were to cool
1ºC, the freeze line would move 1,000 kilometers south.)

Over recent decades, the Sun has been very active. Researchers at the Max Planck Institute for Solar System Research in Germany reported that from 1940 to 2005, solar activity was higher than it had been in the past 1,000 years. They were quick to point out that this activity could not account for all of the recent global warming (particularly that since 1980), but that it was probably a factor.

The period of heavy solar activity may be coming to a close. During 2007-09, the end phase of Solar Cycle 23, the Sun set space-age records for low sunspot counts, weak solar winds, sand low solar irradiation. Current Solar Cycle 24's activity has been slow to start and Hathaway has predicted that this cycle will be the weakest, or quietest, in a century. (This should reduce the risk of a "global Katrina"!) He also predicted that Solar Cycle 25 will be even more feeble.

Now other scientists are agreeing with this analysis. Not only does the current sunspot cycle seem quiet, but also a number of recent reports have indicated a slowing of overall solar activity. These include studies that show:

◘ Sunspot magnetic fields have been steadily decreasing in strength since 1998.

◘ Streamers of the Sun's gassy outer envelope normally develop around the Sun's poles a few years before peak solar storm activity. They should have appeared as early as 2011. They did not.

◘ Jet streams that have formed inside the Sun at this time in every other cycle are not appearing.




Ah, but ice ages (even "little" ones) can last than the summer rerun season.

Scientists have been quick to reassure the public that there is no need to worry. Historically, it took several quiet cycles in a row to produce dramatic cooling--and that was before man-made greenhouse gasses entered the picture. Indeed, some scientists are claiming that a quiet Sun may slow down global warming as well as generate fewer solar storms to disrupt satellites and power systems.

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The National Solar Observatory scientists won't discuss the effects of a quiet Sun on world temperatures or global warming. Too much is unknown. However, Dr. Hill made this observation: "If our predictions are true, we'll have a wonderful experiment that will determine whether the Sun has any effect on global warming."

In June 2011, scientists from the National Solar Observatory warned that if then-current trends continued, the Sun's magnetic fields would be too weak to generate visible sunspots by 2022. In the words of Dr. Frank Hill, associate director of the National Solar Observatory's Solar Synoptic Network, "The solar cycle is maybe going into hiatus, sort of like [a t.v. show in summer]."

According to astronomers, the year 2013 may be an unlucky one, featuring solar flares that blast Earth with hot, ionized gas. Solar Cycle 24 is reaching its maximum, and our satellites and electrical grids are at risk! In the words of Sir John Beddington, the United Kingdom's chief scientific advisor, during a February 2011 meeting of the American Association for the  Advancement of Science, a sever storm could cause a "global Katrina" that would cost the word's economies as much as 52 trillion.

Chilling, isn't it?


I have to say I found this article to be reassuring, for the simple fact that a couple of weak solar activity cycles would help us out from this overweening fear of "global warming", a phenomena that is normal to all planets. I do not mean the Ozone hole that opened up in 1980 -- that was scary as hell --which is exactly as should have been. When human hubris causes the damage, that is one thing. When it is a facet of solar influences, it is normal and natural and part of the ecology of the planet.

So all of you who love to run around ascribing fear to the idea of global warming run rampant, here's your call to calm down and let it go. This Solar Cycle 24 and Solar Cycle 25 will prove to be our friend.

Of course, then, you'll all bitch about the snow!

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