Category Archives: sunspots

Coupling Sun and Earth

The Butterfly Effect, Writ Large

Have you ever heard of the Butterfly Effect? This is part of chaos theory that says a butterfly flapping its wings in Brazil could set off a tornado in Texas. It means that a tiny change in one part of a system can be magnified and ultimately cause something huge elsewhere.  It isn’t limited to systems here on Earth — in fact, scientists are finding out that changes on the Sun can have major effects on Earth’s magnetosphere and upper atmosphere. This is a very important area of study — and one that I touched on in a project we (Loch Ness Productions) did for MIT’s Haystack Observatory about spaceweather.  You can watch the final episode below, where we talk about how all of Earth’s atmospheric layers are coupled together and how a change in one (say from a bout of space weather affecting the ionosphere) can ripple through the system.

As it turns out, large changes in the Sun’s energy output may have a major effect on the thermosphere — one of the upper layers of our planet’s atmosphere. It ranges up from 90 to 500 kilometers above Earth’s surface, and it’s the place where solar radiation makes its first contact with our planet.

Solar activity, courtesy NASA/SDO.

Atmospheric physicists at the National Center for Atmospheric Research (NCAR)’s High Altitude Observatory and the University of Colorado have found that the solar cycle (keyed to the Sun’s magnetic cycle, which produces varying numbers of sunspots over an 11-year period) has other variations, and these affect the thermosphere. If it isn’t bombarded as much by solar radiation, it cools and shirnks.

As it turns out, the Sun’s energy output declined to unusually low levels from 2007 to 2009, a particularly prolonged solar minimum during which there were virtually no sunspots or solar storms. During that same period of low solar activity, Earth’s thermosphere shrank more than at any time in the 43-year era of space exploration. The current research suggests that the Sun was going through a period of relatively low activity, similar to periods in the early 19th and 20th centuries. This could mean that solar output may remain at a low level for the near future. And, the thermosphere could remain smaller than usual. This is good news for orbiting satellites and the International Space Station — they can maintain their current orbits without encountering as much atmospheric drag. On the other hand, during the current solar “maximum”, when solar activity is expected to be at its highest during the 11-year cycle, the Sun’s outbursts like the ones in the SDO animation above could ramp up unexpectedly, threatening us and our technology.

Learning about how the Sun and Earth interact is an important part of astronomy research. Up until a century or so ago, our knowledge of the Sun was pretty rudimentary. Today, after decades of research using both ground-based and space-based observatories (including radar dishes, GPS signals and other methods), astronomers are getting a better handle on the coupled Sun-Earth system.

To learn more about long-term variations in the Sun’s activity, check out these pages at the NCAR/HAO Web site:  http://www.hao.ucar.edu/research/lsv/lsv.php.

 

Solar Storm!

What You Should Know

The March 7th CME. Courtesy SOHO.

I see that “big” media has picked up on the idea of solar storms, in the wake of two most recent and very strong X-class events on the Sun. The headlines are breathless and I’ve already spotted some science bloopers on some sites that should know better (sites that used to have good science reporters, but who let them go in order to concentrate on important things, like Snooki’s baby).

Anyway, for all news about solar activity, I first turn to Spaceweather.com. The folks there have noted the impact of the coronal mass ejection was light at first, but warn it could pick up in the coming hours. Thus, people who live at high latitudes — northern regions around 50 degrees north or more — should get to see even MORE auroral displays than usual. If the storms get strong enough, those of us at lower latitudes might get to glimpse some aurorae, too.

All this solar activity is actually pretty much on schedule for the Sun. It goes through cycles of high and low activity, and we’re headed into a time of very high activity called “solar maximum”.  So, increased numbers of flares and coronal mass ejections and sunspots are part of this process.  It’s perfectly normal and nothing to get worried about. But, there will be the big media reports, and there will be some fascinating whack jobs tying this to something mysterious and paranormal.

Check out MIT Haystack Observatory's Space Weather FX vodcasts at the link below!

That, too, is perfectly normal and nothing to get excited about.

Space weather, which is a term that covers all the solar-caused and geomagnetic disturbances that occur in near-Earth space, does have its down sides.  While we gaze at lovely aurorae, giant disturbances in Earth’s uppermost atmospheric layers and nearby space can disrupt power grids, satellite communications, GPS signals, and many other bits of our modern technology. So, that IS of concern,  and during such events you will read reports that warns of GPS outages or communications outages due to space weather (solar storms). This happens because these bits of technology rely on radio signals which bounce off the layers of our atmosphere in order to propagate (travel) long distances on our planet. In the case of GPS, those signals go THROUGH the atmosphere.  So, if the upper atmosphere is disturbed by space weather, those signals can get broken up, delayed, or even lost. It’s an interesting and potentially dangerous side-effect of living near a star.

A while back we worked with MIT’s Haystack Observatory on a series of short videos about space weather. The series is called Space Weather FX. You can watch the whole series here and learn more about the effects that the Sun has on us and our technology.  Also keep an eye on Spaceweather.com for the latest and most accurate info on solar activity.