At least seven sunspot groups dot the sun this morning at 10 a.m. (CDT) as photographed by NASA’s Solar Dynamics Observatory (SDO). Sunspots are cooler regions where magnetic energy is concentrated. Sometimes that energy is released as a solar flare, propelling solar particles and radiation toward the Earth. Credit: NASA
Like you and I the sun has cycles. None of us escapes the day-night rhythm of sleep and wakefulness. The most visible of the sun’s rhythms is the 11 year solar cycle also called the sunspot cycle. These vary from 9 to 14 years but the average is 11.
In a typical cycle, the number of sunspots and solar storms begins at a minimum, rises to a maximum and then returns to minimum. During solar maximum the sun is peppered with sunspots and powerful, aurora-producing flares are common; at minimum the sun’s face can be blank for days or even weeks. Minimums and maximums also vary. Some peaks are longer and more sunspot-rich than others, while “valleys” can be short or long with variable spot numbers.
The peaks and valleys of the past 110 years of solar cycles. Sunspot numbers (shown at left) wax and wane in an approximately 11-year cycle.
The solar cycle was discovered by German astronomer Samuel Heinrich Schwabe in 1843 after he noticed sunspot numbers wax and wane in a regular pattern after 17 years of observation. Swiss astronomer Rudolf Wolf went back through previous sunspot records and reconstructed the sun’s ups and downs as far back as the mid-1700s.
Samuel Heinrich Schwabe
Each cycle gets a number. Solar Cycle 1 spanned the years 1755 to 1766. The last, Cycle 23, peaked in April 2000 with an average of 120 sunspots per day around the time of maximum. This was followed by a deep quiet period or minimum between cycles 23 and the current 24th with a record number of 801 spotless days between October 2005 and May 2010. This past solar minimum, which bottomed out in December 2008, was the longest and quietest in over a century. Since then, but especially over the past year, activity has been steadily on the rise.
The graph shows the last sunspot maximum in 2000 up through June this year. The current Cycle 24 is predicted to reach maximum next spring with an average of 60 spots a day. This would make it the smallest maximum in over 100 years. Credit: NASA
2012 has been a good year for sunspots, solar flares and auroras as we dig our way out of minimum and sail toward the next predicted peak in spring 2013. To date, the sun has kicked off about a half-dozen X-class flares. These are the most powerful variety with potential effects on Earth ranging from aurora creation to wreaking havoc with satellites and power grids. From late 2008 through early 2010 I recorded almost no auroras here in Duluth, Minn. In the past year however, we’ve been treated to several brilliant displays and at least 10 minor ones.
The brilliant flash is a powerful solar flare that erupted in March 2012. Flares can affect the upper atmosphere (auroras), airplane communications, satellites, power grids and oil pipelines. Click image to see a spectacular video of a solar eruption that happened yesterday. Credit: NASA
NASA solar scientists predict a very weak maximum in 2013 with an average of 60 sunspots daily. If this holds true, Cycle 24 would be the least active since Cycle 14 which peaked in February 1906 at 64. While this sounds like bad news for aurora watchers, don’t put on your long face just yet. Every cycle max, even the wimpier ones, feature powerful flares and crazy space weather.
“Even a below-average cycle is capable of producing severe space weather,” says Doug Biesecker of the NOAA Space Weather Prediction Center. “The great geomagnetic storm of 1859, for instance, occurred during a solar cycle of about the same size we’re predicting for 2013.”
That storm, called the Carrington Event, is named after astronomer Richard Carrington who spotted a brilliant flare through his telescope on September 1, 1859. Shortly before dawn the next day, the sky blew up in a brilliant display of northern lights visible as far south as Jamaica. Aurora-induced electric currents in telegraph lines shocked telegraph operators and set telegraph paper on fire.
“A report by the National Academy of Sciences found that if a similar storm occurred today, it could cause $1 to 2 trillion in damages to society’s high-tech infrastructure and require four to ten years for complete recovery,” according to a recent NASA press release.
We’ll soon see what Cycle 24 has in store. At the very least, more brilliant auroras are on the menu.
I am looking forward to an active cycle..In 1957 ham radio was blessed with great
action on all bands. My favorite ham band is 10 meters where little rf power will get
you contacts around the world…Do you suppose we can look forward to that?
This time around there are probably not many CB xcvrs left–hopefully.
Here’s hoping that sunspot activity will increase..I have seen two flaming coronas in my life time–the first was 1938- 2nd in late 60′s or early 70′s-entire sky was red! 73
Walter,
I don’t do ham radio but I’ve enjoyed shortwave listening (and listened to quite a few hams on the sidebands)for years with my Drake R-8. 1957 was a record solar max in the past hundred years-plus. I hope we get another one like it in our lifetimes. Happy listening!
We are constantly discussing the events of the Sun, and still do not know the real causes, whose effects on the Earth can be caused by damage to a couple of trillion dollars.
I ask:
How many millions of dollars to give civilization on Earth to know exactly predict the occurrence and prevent damage.?
Tell me a percentage of the damages.
I can help. I declare very seriously.
oh haha well in that case just name your price
hi Bob, noted the rather strong max in the late 1940′s. I recall some rather spectacular auroras during that period, especially in 1947-48.
Bob, do you think there’s a definite connection between the sun’s output and climate change, whether it be warming or cooling?
Tough one Carol. There’s a clear connection between the sun’s output and the warming of Earth’s outer atmosphere. These are cyclic variations from one solar maximum to the next. Over the lifetime of the solar system the sun’s output has probably undergone changes that have resulted in climate change on Earth. As for the current climate trend – it’s not due to a change in the energy output from the sun.
Thanks Bob. I wasn’t sure. Given the correlation between the Maunder Minimum and the Little Ice Age, I was wondering if there was any correlation in modern times.
Carol,
Ah, yes. I’d forgotten about that. Yes, there is possibly a connection there between the sun and climate during that long period of no sunspots. Here’s a great article on the topic: http://earthobservatory.nasa.gov/IOTD/view.php?id=7122
Interesting article, Bob. Thanks for posting. I wonder why (and it’s not explained) the LIA was seemingly confined to the Northern Hemisphere? There’s no mention, nor illustration, of conditions in the Southern Hemisphere.
I know Carol – I wondered about that too. I’m not fully convinced the change was due to sunspots. Almost convinced but still a bit skeptical.
Thanks for linking that article, Bob; it tells a good story. The key point is that while the total solar irradiance TSI might decrease just a few tenths of a percent, cooling the earth a mere fraction of a degree, the UV solar flux varies much more greatly. That can tweak the stratosphere and work down to the troposphere, as the article says. Then it kicks the atmospheric waves over the oceans. Note the big warm blobs over the North Pacific and North Atlantic, which sends the jet stream diving south into the US and Europe, bringing the cold. So it’s a way for otherwise modest changes in the Sun to affect a large change in our climate.
These ocean changes/cycles go by names like the Pacific Decadal Oscillation and Atlantic Multidecadal Oscillation, and along with El Nino are the biggest things affecting hot summers, cold winters, hurricanes, droughts, etc. over the northern land masses. Long-range forecasters use them to predict (with slight success) what kind of winter it will be, for example.
As for the southern hemisphere, since there’s so much water and so little land, the jet stream waves don’t get as strong and things are more consistent.
If you want to hear more, I’m giving a talk on this stuff on the Sky & Telescope eclipse cruise in November. So you can toast your toes in the Coral Sea while I talk abut how cold it got in Duluth.
Richard,
It does sound a like a “butterfly effect” scenario. I’d love to hear your talk while floating in the Coral Sea. That just sounds like a good place for a Duluthian to be in November.
Woah. Crazy. Thanks for this I had never heard of this phenomena.
Found some info on the Little Ice Age in the Southern Hemisphere:
http://www.agu.org/pubs/crossref/2012/2012GL051260.shtml
It seems there WERE some effects, especially in the West Antarctic Ice Sheet.
Strong flares from the sun is not an indication of a strong cycle. Solar Cycle 24 is very weak. It is much weaker than most folks realize at 1/20th of the x-ray and UV emissions compared to a normal cycle. This has to have an affect on weather.
Given the high probability for a grand minimum, you can kiss ham radio as we now know it good bye too.
Henry,
Agreed. Cycle 24 is definitely a weak one thus far. For the record, consistent, major flares from the sun are one sign of a strong cycle.
“The great geomagnetic storm of 1859, for instance, occurred during a solar cycle of about the same size we’re predicting for 2013.”
Hmmm… it could yet get very interesting, eh?
Was that flare or CME in 1859 particularly big and powerful? Or did it have those effects just because it was a direct hit on the Earth? Maybe there isn’t really any way to know for sure, eh?
Bob,
The flare was extremely powerful – plainly visible in white light – and situated so that its radiation was Earth-directed. Most flares are only seen through a special H-alpha filter. If I’m not mistaken, the 1859 flare created the largest geomagnetic storm ever recorded on Earth. I’m not sure when the quote comparing the current cycle with the 1859 one was written, but this cycle’s maximum is expected to be considerably lower than many, including that of 1859. No matter what the overall cycle strength, the potential for powerful solar flares is there.