|Solar flares do not pose a direct danger to earth|
|A solar flare expanding from the sun|
Probably as a consequence of the recent release of the movie “Knowing”, this particular claim has jumped in frequency, with many now equating ‘massive solar flares’ with mass destruction on earth.
Here are the facts:
- There are solar flares all of the time.
- The number of flares (and sunspots) varies over time in an approximate eleven-year cycle.
- The Sun was due to reach a maximum (called ’solar max’) in its 11 year cycle in 2011 or 2012. However, more recent observations have pushed this date off to sometime in 2013.
New Scientist Article
There is an article published on the New Scientist website, based on a report by NASA and the National Academy of Science in which a hypothetical massive solar storm causes a long-term disruption in the electrical power grid.
The strongest solar storm on record is called the “Carrington Event” (after Richard Carrington who viewed and reported on the solar flare of September 1st). It occurred in late August and early September of 1859. From August 28th through September 4th, aurorae of unusual brilliance were observed throughout North and South America, Europe, Asia, and Australia, and were seen as far south as Hawaii, the Caribbean, and Central America in the Northern Hemisphere and in the Southern Hemisphere as far north as Santiago, Chile.
A Carrington Event today
Should such an event occur today, there would be massive disruption in electrical grids, possibly long term. What is needed is to beef up our early warning system, and to stockpile spares of critical components. However, the report paints a worst-case scenario where no warning is given, and the electrical grid operators do not have time to take precautions.
The "South Atlantic Anomaly"
Over the South Atlantic and parts of South America there is a 'weak spot' in the magnetic field. This caused by the orientation of the earth's magnetic field. The magnetic poles are offset a bit from the axis of rotation, and this brings the Van Allen Belts a bit closer over this region. This creates an area where charged particles can penetrate deeper into the magnetosphere than they can in other areas.
This anomaly was discovered at the dawn of the space age. Shortly after the first satellites flew, it was noticed that they encountered problems with the satellites over this area consistently.
The "Giant Breach" in the magnetosphere
NASA's five THEMIS (Time History of Events and Macroscale Interactions during Substorms) satellites were launched to investigate the near-earth space weather, the interaction between the earth's magnetic field and the charged particles streaming in from the Sun. On June 3, 2007 the five spacecraft flew through a breach in the magnetosphere just as it opened. There were some important and 'game changing' discoveries made, including the fact that the polarity of the solar wind was aligned with the earth's. Conventional wisdom up to that point was that this should reinforce the magnetosphere, but instead it created a breach. Scientific investigations are still proceeding.
It is important to recognize that this 'giant breach' was a transient event. There is no "giant hole" in the magnetosphere as a result of this event.
NCAR Prediction in June 2006
In 2006, the National Center for Atmospheric Research issued a press release indicating that the next solar cycle would be stronger than normal, as much as 30 to 50% stronger than the 2001 solar max.
So far, we have a lousy record of predicting the intensity of solar maximum, and this report was no exception. It was based on a 'conveyer belt model' of the sun, and based its predictions on observations of sunspots in the previous cycle.
NASA prediction in May 2009
However, the sun is behaving oddly, and nearly three years after the NCAR report, in May 2009, NASA released a new report that says that "Solar Cycle 24 will peak, they say, in May 2013 with a below-average number of sunspots."
Even if the original prediction was still valid, we still have this question: What relevance is it to us?
The authors of the NCAR paper said that cycle 24 may be stronger than usual, and perhaps as strong as the 1956 solar max. Did we all die in 1956, or 1859 for that matter?
No Killer Solar Flare
Specifically, there is no prediction of a massive life-killing solar flare. Even more specifically, there is no evidence that our sun can produce a ‘Knowing’ type solar flare anytime soon. We know what stars like our sun are capable of by looking at other sun-like stars. If these stars were churning out massive CMEs like the movie ‘Knowing’ depicted, then we would see that in other stars… and we don’t.
We question the terminology used by the proponents of a strong solar flare in 2012. The sun is unpredictable, and it can send a massive coronal mass ejection in our direction at any point in time, regardless of the sunspot cycle.
Specifically we question the clear implication that the sun is going to send a stronger solar flare at solar max than it would at the solar minimum. The "maximum" is the maximum amount of sunspots and other magnetic solar activity. It does not mean that the sun only sends out solar flares during solar max. In fact, the biggest geomagnetic storm ever recorded happened during a solar minimum. In addition, as Tony Darnell points out in this video the "Halloween Storms" of 2003 occurred 3 years after solar max.
Likewise, the sun is perfectly capable of not generating a lot of solar flares or CMEs, even during solar max. Activity tends to be more frequent during solar max, but not necessarily stronger.
Study of the Sun
NASA is launching the "Solar Dynamics Observatory" which will study the sun in unprecedented detail. Here is a nice graphic from the New York Times describing the SDO satellite. This is a good thing, it is always important to improve our knowledge of potential hazards. This does not mean that NASA is "worried about massive solar flares". Some people try to imply that wherever NASA puts missions it is 'worried' or 'concerned' about some threat. We see this frequently from various sources. As mentioned by Ian O'Neill in the comments, the annual threat from solar events is miniscule, and the worst that can generally happen is a disruption in power or communications.
In Conclusion, we have shown that predictions of a stronger than normal solar cycle are massively overstated.