View Full Version : Sun Makes History: First Spotless Month in a Century

09-05-2008, 07:21 AM
Michael Asher (Blog) -
September 1, 2008 8:11 AM

Drop in solar activity has potential effect for climate on earth.

The sun has reached a milestone not seen for nearly 100 years: an entire month has passed without a single visible sunspot being noted.

The event is significant as many climatologists now believe solar magnetic activity – which determines the number of sunspots -- is an influencing factor for climate on earth.

According to data from Mount Wilson Observatory, UCLA, more than an entire month has passed without a spot. The last time such an event occurred was June of 1913. Sunspot data has been collected since 1749.

When the sun is active, it's not uncommon to see sunspot numbers of 100 or more in a single month. Every 11 years, activity slows, and numbers briefly drop to near-zero. Normally sunspots return very quickly, as a new cycle begins.

But this year -- which corresponds to the start of Solar Cycle 24 -- has been extraordinarily long and quiet, with the first seven months averaging a sunspot number of only 3. August followed with none at all. The astonishing rapid drop of the past year has defied predictions, and caught nearly all astronomers by surprise.

In 2005, a pair of astronomers from the National Solar Observatory (NSO) in Tucson attempted to publish a paper in the journal Science. The pair looked at minute spectroscopic and magnetic changes in the sun. By extrapolating forward, they reached the startling result that, within 10 years, sunspots would vanish entirely. At the time, the sun was very active. Most of their peers laughed at what they considered an unsubstantiated conclusion.

The journal ultimately rejected the paper as being too controversial.

The paper's lead author, William Livingston, tells DailyTech that, while the refusal may have been justified at the time, recent data fits his theory well. He says he will be "secretly pleased" if his predictions come to pass.

But will the rest of us? In the past 1000 years, three previous such events -- the Dalton, Maunder, and Spörer Minimums, have all led to rapid cooling. One was large enough to be called a "mini ice age". For a society dependent on agriculture, cold is more damaging than heat. The growing season shortens, yields drop, and the occurrence of crop-destroying frosts increases.

Meteorologist Anthony Watts, who runs a climate data auditing site, tells DailyTech the sunspot numbers are another indication the "sun's dynamo" is idling. According to Watts, the effect of sunspots on TSI (total solar irradiance) is negligible, but the reduction in the solar magnetosphere affects cloud formation here on Earth, which in turn modulates climate.

This theory was originally proposed by physicist Henrik Svensmark, who has published a number of scientific papers on the subject. Last year Svensmark's "SKY" experiment claimed to have proven that galactic cosmic rays -- which the sun's magnetic field partially shields the Earth from -- increase the formation of molecular clusters that promote cloud growth. Svensmark, who recently published a book on the theory, says the relationship is a larger factor in climate change than greenhouse gases.

Solar physicist Ilya Usoskin of the University of Oulu, Finland, tells DailyTech the correlation between cosmic rays and terrestrial cloud cover is more complex than "more rays equals more clouds". Usoskin, who notes the sun has been more active since 1940 than at any point in the past 11 centuries, says the effects are most important at certain latitudes and altitudes which control climate. He says the relationship needs more study before we can understand it fully.

Other researchers have proposed solar effects on other terrestrial processes besides cloud formation. The sunspot cycle has strong effects on irradiance in certain wavelengths such as the far ultraviolet, which affects ozone production. Natural production of isotopes such as C-14 is also tied to solar activity. The overall effects on climate are still poorly understood.

What is incontrovertible, though, is that ice ages have occurred before. And no scientist, even the most skeptical, is prepared to say it won't happen again.

Article Update, Sep 1 2008. After this story was published, the NOAA reversed their previous decision on a tiny speck seen Aug 21, which gives their version of the August data a half-point. Other observation centers such as Mount Wilson Observatory are still reporting a spotless month. So depending on which center you believe, August was a record for either a full century, or only 50 years.
http://www.dailytech.com/Sun+Makes+History+First+Spotless+Month+in+a+Centur y/article12823.htm

09-24-2008, 08:30 PM
Sun's Power Hits New Low, May Endanger Earth?

Anne Minard
National Geographic News (http://news.nationalgeographic.com/)

September 24, 2008

Even the sun (http://science.nationalgeographic.com/science/space/solar-system/sun-article.html?nav=A-Z) appears headed for a recession. The Ulysses space probe (http://news.nationalgeographic.com/news/2008/02/080225-AP-solar-probe.html) has detected fewer sunspots, decreased solar winds, and a weakening magnetic field—the lowest solar activity observed in 50 years, NASA scientists said yesterday.

That translates into a shrinking of the heliosphere, the invisible buffer that extends beyond Pluto and guards the planets (http://science.nationalgeographic.com/science/space/planets)—ours included—from bombardment by cosmic rays.

Speaking yesterday at a NASA teleconference, scientists refused to draw conclusions from their observations, especially with respect to whether the changes are influencing Earth's climate.

"That area of science is in the realm of speculation at this point," said Nancy Crooker, a researcher at Boston University.

But David J. McComas of the Southwest Research Institute, who leads one of the experiments onboard Ulysses, called the changes "significant."
"This is a whole-sun phenomenon. The entire sun is blowing significantly less hard than it was 10 to 15 years ago," he said.

"Over the entire record of sun observations, this is the longest prolonged low pressure that we've observed."

Some variance in solar activity is normal for the sun, which has a 22-year magnetic cycle and an 11-year sunspot cycle.

But McComas said in a statement that researchers have been "surprised to find that the solar wind is much less powerful than it had been in the previous solar minimum."
Ed Smith, a NASA Ulysses project scientist at the Jet Propulsion Laboratory in Pasadena, California, also added that the drop in solar winds has lasted longer than predicted.

Scientists noted that while solar activity is low compared to the past 50 years of data, the sun's output has dipped before. early 1600s Galileo and other astronomers observed only about 50 sunspots over a 30-year period. Normally, the early scientists would have witnessed closer to 50,000.

Scientists have also speculated for centuries about an intuitive link between the sun's intensity and Earth's climate (http://news.nationalgeographic.com/news/2007/07/070712-sun-climate.html).

There is evidence of the sun causing short-term impacts on Earth's weather.

The so-called Maunder Minimum, a time of low solar activity, lasted from about 1645 to 1715. During this time, access to Greenland was largely cut off by ice, and canals in Holland routinely froze solid, according to NASA.
Glaciers advanced in the Alps, and sea ice increased so much that no open water flowed around Iceland in the year 1695.

The latest observations show that the sun is even more mercurial than previous research could have found. "The sun is a variable star after all," Crooker said.

Less protection from the sun's heliosphere may also make space exploration more dangerous, according to Crooker.
Astronauts could encounter more lethal cosmic rays without the sun's protection, for example.

Most of the effects of a shrinking heliosphere, however, will be felt billions of miles beyond Pluto, at the edges of the sun's influence.
If the solar wind stays weak, NASA's Voyager 1—launched in 1977 and now headed beyond our solar system—should reach the edge of the heliosphere earlier than expected, becoming the first craft to enter interstellar space.

Launched in 1990, the joint NASA and European Space Agency Ulysses mission has lasted four times longer than expected.
The probe, which is slowly freezing to death and is expected to shut down within months, observed a dramatic slowdown in solar activity during its third and final orbit around the sun last year.
(Learn how satellites are probing secrets of the sun (http://ngm.nationalgeographic.com/ngm/0407/feature1/).) While the demise of Ulysses is imminent, NASA will soon develop the Solar Probe mission, which will fly close to the sun to determine what heats its corona—the outer layer—and accelerates solar wind.


09-24-2008, 08:36 PM
Actually, you just gave me the excuse to expand on what I wrote.
If you look at the Vostok data, it says that "something" tipped, even without the aid of man, about once every 117,000 years.
What I have been suggesting is: once the ocean gets warm enough to power "getting the ball rolling", it does not take much. If the ocean is not warm enough, little things like the Little Ice Age (which had less than the 2C change that I suggest is necessary) can start the ball rolling, but the ocean did not have the energy to accelerate it to "unstoppable".
If you look closely at the detail, in every one of the last four cases, the one thing we see is that the "big plunge" takes hold after a peak high, not after a plateau.
I'm suggesting that the missing link was the accumulated energy in the ocean, not the petty little peak in atmospheric temperature.
Hey, I put the proposition forward so everyone could have a whack at it. Please do!

09-24-2008, 08:58 PM
Solar wind blows at 50-year low

By Jonathan Amos
Science reporter, BBC News

http://newsimg.bbc.co.uk/media/images/45045000/jpg/_45045117_ulysses.jpg Engineers expect contact to be lost with Ulysses very soon

The solar wind - the stream of charged particles billowing away from the Sun - is at its weakest for 50 years.
Scientists made the assessment after studying 18 years of data from the Ulysses satellite which has sampled the space environment all around our star.
They expect the reduced output to have effects right across the Solar System.
Indeed, one impact is to diminish slightly the influence the Sun has over its local environment which extends billions of kilometres into space.
http://newsimg.bbc.co.uk/shared/img/o.gifhttp://newsimg.bbc.co.uk/nol/shared/img/v3/start_quote_rb.gif Even though the end is now in sight, every day's worth of new data is adding to our knowledge of the Sun and its environment http://newsimg.bbc.co.uk/nol/shared/img/v3/end_quote_rb.gif

Richard Marsden
Esa's Ulysses project scientist

Confirmation of that prediction should come from the far-distant Voyager spacecraft which were launched in the 1970s and are now bearing down on the edge of the heliosphere - the great "bubble" of wind material that surrounds the Sun.
Scientists now predict the Voyagers will hit the edge and cross over into interstellar space - that region considered to be "between the stars" - sooner than anticipated.

Space age
The solar wind, which originates in the Sun's hot outer atmosphere known as the corona, gusts and calms with the star's familiar 11-year cycle of activity (but also over its less well known longer cycles, too).
Calmer wind conditions would be expected to prevail right now, but the Ulysses data indicates circumstances unprecedented in recent times. http://newsimg.bbc.co.uk/media/images/45047000/jpg/_45047524_sun.jpg The Sun is a variable star; activity rises and falls in cycles

"This is a whole Sun phenomenon," said Dave McComas, Ulysses solar wind instrument principal investigator, from Southwest Research Institute, San Antonio, US.
"The entire Sun is blowing significantly less hard - about 20-25% less hard - than it was during the last solar minimum 10-15 years ago.
"That's a very significant change. In fact, the solar wind we're seeing now is blowing the least hard we've see it for a prolonged time, since the start of those observations in the 1960s at the start of the space age."

In addition to being calmer, the wind measured at Ulysses is 13% cooler.

However, judging from Sun activity data collected by non-satellite methods over the past 200 years, the current behaviour is thought to be well within the long-term norm.
Nonetheless, scientists expect the weakened wind to have a wide range of impacts.

Energetic rays
The charged wind particles also carry with them the Sun's magnetic field, and this has a protective role in limiting the number of high-energy cosmic rays that can enter the Solar System.
More of them will probably now make their way through.
Many of these rays, which include electrons and atomic nuclei, originate in exploding stars and at black holes, and move at colossal speeds. http://newsimg.bbc.co.uk/media/images/45047000/jpg/_45047525_voyager.jpg The Voyager spacecraft will move beyond the solar wind's influence

They pose no major risk to people on Earth because our atmosphere also works to reduce their intensity; but they are a consideration for space operations.
The rays can damage satellite electronics, and if current solar wind conditions persist, engineers would have to take this into account when deciding how to "harden" their spacecraft. Astronauts, too, are at risk from the higher doses of radiation associated with cosmic rays.

"The Sun also puts out cosmic rays in the form of bursts and these bursts are much less frequent at solar minimum. However, when they do occur at solar minimum, they are more lethal, so this is not a good time to be travelling in space owing to both kinds of cosmic rays," explained Professor Nancy Crooker, from Boston University, Massachusetts, US.

"Reduced solar activity also leads to the cooling of Earth's upper atmosphere and if Earth's upper atmosphere is cooler then there is less drag up there on satellites and this means we are left with much more debris up there - which is also something astronauts have to look out for."
Some researchers have attempted to link the intensity of cosmic rays at Earth to cloudiness and climate change. Current conditions may be a good opportunity to test these ideas further.
http://newsimg.bbc.co.uk/media/images/45045000/jpg/_45045207_sunenvironment.jpg Artist's impression: The wind forms a bubble of material around the Sun

The Ulysses mission is a co-operative venture between the US space agency and the European Space Agency (Esa). Launched by the shuttle in 1990, it was the first satellite to study the space environment above and below the Sun's poles.

It samples the solar wind and solar magnetic field as it circles the star in a six-year orbit that also carries it out to Jupiter and back.

But the harsh conditions of space are now slowly taking their toll on the spacecraft.

Ulysses' main transmitter no longer works and it is struggling to put enough power into its heating systems. With the satellite currently moving away from the Sun, it is gradually getting colder; and engineers expect the hydrazine fuel used in its thrusters to freeze very soon.
When this happens, Ulysses will no longer be able to orientate itself and its antenna, and contact will be lost with Earth.
"Even though the end is now in sight, every day's worth of new data is adding to our knowledge of the Sun and its environment; and it's been a great and exciting mission," said Richard Marsden, Esa's Ulysses project scientist and mission manager. Jonathan.Amos-INTERNET@bbc.co.uk (Jonathan.Amos-INTERNET@bbc.co.uk)

09-25-2008, 07:51 PM
Lowdown on the sun
By Ron Cowen (http://www.sciencenews.org/view/authored/id/65/name/Ron_Cowen)

50 years, and the unusually long lasting solar minimum offers hints about the wind’s origin.
<DIV class="content_content print" style="FONT-SIZE: 12px; COLOR: #000000">

Every 11 years, the sun gets the doldrums. Solar storms are fewer and the strength of the solar wind, the stream of charged particles blown from the sun, declines. But new spacecraft observations have now gotten the true lowdown: The current solar minimum is the lowest — and one of the longest — recorded in the past 50 years, since modern measurements began
This period of low solar activity has already lasted six months longer than the last solar minimum, which was in 1994 and 1995.


US Blues
09-25-2008, 10:37 PM
Here's a site that updates daily sunspot and solar flux


D. Gale
09-26-2008, 01:28 PM
Another good site for sunspot activity and other solar news.