Predicting space weather is not for the faint-hearted. Although the Sun appears to have a predictable and regular cycle of activity, the details are a lot more complex. So complex in fact, that the world’s greatest research institutions have to use the most powerful supercomputers on the planet to simulate the most basic of solar dynamics. Once we have a handle on how the Sun’s interior is driven, we can start making predictions about how the solar surface may look and act in the future. Space weather prediction requires a sophisticated understanding of the Sun, but even the best models are flawed.
Today, another solar cycle prediction has been released by the guys that brought us the “$2 trillion-worth of global damage if a solar storm hits us” valuation earlier this month. According to NOAA scientists sponsored by NASA, Solar Cycle 24 will peak in May 2013 with a below-average number of sunspots.
“If our prediction is correct, Solar Cycle 24 will have a peak sunspot number of 90, the lowest of any cycle since 1928 when Solar Cycle 16 peaked at 78,” says Doug Biesecker of the NOAA Space Weather Prediction Center.
Although this may be considered to be a “weak” solar maximum, the Sun still has the potential to generate some impressive flares and coronal mass ejections (CMEs). Although I doubt we’ll see the record-breaking flares we saw in 2003 (pictured top), we might be hit by some impressive solar storms and auroral activity will certainly increase in Polar Regions. But just because the Sun will be more active, it doesn’t mean we will be struck by any big CMEs; space is a big place, we’d be (un)lucky to be staring directly down the solar flare barrel.
So, we have a new prediction and the solar models have been modified accordingly, but it is hard to understand why such tight constraints are being put on the time of solar maximum peak (one month in 2013) and the number of sunspots expected (90, or thereabouts). Yes, sunspot activity is increasing, but we are still seeing high-latitude sunspots from the previous cycle (Solar Cycle 23) pop up every now and again. This is normal, an overlap in cycles do occur, yet it surprises me that any definitive figures are being placed on a solar maximum that may or may not peak four years from now.
We are able to look at the history of sunspot number and we can see the cycles wax and wane, and we can pick out a cycle that most resembles the one we are going through now, but that doesn’t mean that particular cycle will happen this time around. Statistically-speaking, there’s a higher chance of a similar-looking cycle from the past happening in this 24th cycle, but predictions based on this premise are iffy to say the least.
Also, solar models are far from being complete, and many aspects of the physics behind the Sun’s internal dynamics are a mystery. The Sun really is acting strange, which is fascinating for solar physicists.
“It turns out that none of our models were totally correct,” says Dean Pesnell of the Goddard Space Flight Center, NASA’s lead representative on the panel. “The sun is behaving in an unexpected and very interesting way.”
Personally, I think we should concentrate less on predicting when or how the next solar maximum presents itself. Solar models are not going to suddenly predict the nature of the solar cycle any more than we can predict terrestrial weather systems more than a few days in advance.
Using the atmospheric weather analogy, we know the seasons cycle as the year goes on, but there is no way we can say with any degree of certainty when the hottest day of the year is going to be, or which week will yield the most rain.
The same goes for our Sun. It is vastly complex and chaotic, a system we are only just beginning to understand. We need more observatories and more solar missions with advanced optics and spectrometers (and therefore a huge injection of funding, something solar physicists have always struggled without). Even then, I strongly doubt we’ll be able to predict exactly when the peak of the solar cycle is going to occur.
That said, space weather prediction is a very important science, but long-term forecasts don’t seem to be working, why keep on releasing new forecasts when the old one was based on the same physics anyway? Predicting an inactive, active or mediocre solar maximum only seems to cause alarm (although it is a great means to keep solar physics in the headlines, which is no bad thing in my books).
I suppose if you make enough predictions, eventually one will be correct in four years time. Perhaps there will be a peak of 90 sunspots by May 2013, who knows?
If you’re blindfolded, spun around and armed with an infinite supply of darts, you’ll eventually hit the board. Hell, you’ll probably even hit the bullseye…
Source: NASA, special thanks to Jamie Rich for bringing this subject to my attention!
astroengine.com 