July 22, 2019

03.03.11: The Riddle of the Blank Sun: Solved?

Researchers At the Indian Institute of Science and Education and the Harvard-Smithsonian Center for Astrophysics may have shed light on an enduring mystery from the past decade. In an article due to be published today in Nature, Dibyendu Nandi and co-author Andre Munoz-Jaramillo have come up with convincing evidence as to why the past solar minimum of 2008-09 was such a persistent one. During this minimum, over 600 spotless days occurred, the most since the great minimum of 1913. As a result, the outer magnetic sheath of the sun that we reside in shrunk, the Earth’s upper atmosphere cooled due to lower ultraviolet levels and contracted, and an increase of cosmic ray activity was seen in the inner solar system. This subsequently affected the usual drag that is induced on satellites, slowing down the rate of orbital decay and causing a buildup of space junk… just what’s up with our nearest star?

Now, researchers have built a model of the solar interior that fits a description of what has actually occurred; and the trouble started back at the peak of cycle #23 with a speeding up of the “Great Conveyor Belt” of plasma in the suns interior. This magnetic dynamo sub-ducts sunspot activity towards the poles, only to have them “well up” as these conveyors turn in opposite directions in both hemispheres. Paradoxically, a slowing down leads to a relaxing and expansion of the belt, allowing magnetic activity to surface; speeding up meant the activity never had a chance to surface. Sunspot activity usually begins at high latitudes at the beginning of a cycle, a hallmark that the new cycle is indeed underway. As the sunspot cycle progresses, sunspot activity tends to progress to lower latitudes. The model suggested by Nandi and Munoz is built on the buoyant evolution of sunspots versus the interplay of the magnetic dynamo and the meridional flows in the solar interior. This theory may also explain two other lingering mysteries; why are sunspots never seen at polar solar latitudes? Does the sun have longer cycles juxtaposed over the known 11 year one, such as the 70 year cycle that occurred in the 17th century known as the Maunder Minimum?

Researchers will soon have a chance to put all of these models to the test. NASA’s Solar Dynamics Observatory is on solar vigil, and the twin STEREO spacecraft have reached a vantage point giving scientists 360° coverage of the Sun. Solar cycle #24 will see the sun scrutinized as never before. Even today, two new sunspot groups have emerged, and a large prominence looking like an acacia tree can be seen on the limb of the sun from Astroguyz HQ via our trusty PST… the approaching 2013-14 solar maximum may prove to mark a renaissance in solar science.

 

17.06.10: Living with Solar Cycle #24.

As our local star gets underway into solar cycle #24, all eyes, orbiting and ground based, are keeping a close watch. The very concept of space weather is coming very much into vogue, and the activity over the next several year span may test the underpinnings of our technological civilization like never before. This past June 8th, scientists, authorities and civic planners met in Washington D.C. at the Space Weather Enterprise Forum at the National Press Club to discuss what if anything can be done to protect ourselves from the tempestuous throes of the Sun. This next cycle got off to a sputtering start but is forecast to be a rough one; keep in mind, while the solar cycle lasts 11 years, technology as per Moore’s law has been doubling exponentially once every 18 months. Ask yourself, what would you have read this on 11 years ago? And a really nasty flare such as the Carrington event in 1859 would do more than simply put your cell on the fritz; increasingly, everything from emergency services to navigation to commerce depends on technology. Heck, knocking out the power grid on a humid summers’ day might spell death for hundreds… with this apocalyptic setting in mind, the National Academy of Sciences built a report two years ago entitled Severe Space Weather Events- Societal and Economic Impacts, which outlined the possibilities of a really massive solar flare and efforts to minimize its impact. This year’s meeting marks the fourth symposium on the subject. It been suggested by the study that a century class storm could have the impact of Katrina twenty fold, but it is also true that there is simply no precedent for such an event. On the frontlines of the space weather wars are Richard Fisher, head of NASA’s Heliophysics Division, and Thomas Bogdan, director for the NOAA’s Space Weather Prediction Center. Along with ground based networks such as GONG (The Global Oscillation Network Group), three key elements stand at the ready in their Sun monitoring arsenal;

The Solar Dynamics Observatory (SDO). It’s no coincidence that NASA’s premiere solar observing platform took to orbit at the start of the solar cycle; SDO will be able to monitor solar activity with unprecedented detail and resolution.

STEREO: The Solar Terrestrial RElations Observatory, STEREO is actually a pair of satellites, one Earth-leading and one Earth-trailing. This will allow us to peer around the backside of the Sun to see if anything nasty is rotating our way.

But one of the most vital instruments may be the one you’ve never heard of; ACE, or the Advanced Composition Explorer. ACE was launched in 1997 and samples the near Earth solar environment from its upwind position and gives scientists a 30 minute warning before an event begins interacting with our planet.

So what can be done if the big one is on the way? In many instances, equipment can be saved simply by disconnecting transformers or placing satellites in safe mode…but one thing is for certain, we can no longer afford to think that our daily lives are somehow separate from the space environment. Like it or not, we are now a space faring culture, with all that entails. Be grateful that NASA and the NOAA are on continued solar vigil!