Thursday, 9 June 2011

Massive Solar Flare Misses Earth, but Are We Ready for the Big One?

solar flare


Although yesterday's solar flare won't seriously harm the Earth, the potential for an extreme event is on the rise. Is the world prepared?

By Peter Pachal20digg


Massive Solar Flare Misses Earth, but Are We Ready for the Big One? How to Prepare for a Major Solar Storm

The Sun roared out a huge solar flare yesterday. NASA caught it on film, ranking the spectacular blast as a Class-M flare, just one spot below the the most disruptive type of flare, X. Even so, NASA says it will give Earth a mere "glancing blow," and the National Weather Service expects it will cause only minor disruptions to satellites and power grids.

It could have been much worse. For centuries, solar flares have been responsible for a multitude of earth-bound calamities, from blackouts to disrupted communications to strange lights in the sky. In 1859, the biggest flare on record hit, creating auroras worldwide and interrupting telegraph service for weeks. Considering today's connected world—and our reliance on satellites—a major solar storm could be disastrous.

The sun is entering a particularly active time, says NASA, and big flares like the one from yesterday will likely be common during the next few years, with solar activity expected to peak around 2013. Most solar flares will only cause minor problems with satellites and power grids, but there's always a chance that a monster like the one from 1859 could hit.

"The worst-case scenario is an extreme event," says Michael Hesse, chief of NASA's Space Weather Laboratory at the Goddard Space Flight Center in Maryland. "If it were to happen and we don't take any precautions, it would probably knock out our power grid for an extended period of time and destroy a sizable fraction of our satellite infrastructure."

"This is not something we expect to happen tomorrow," he cautions. "But it's like the impact of a hurricane on a specific location. You don't expect it to happen tomorrow, but you might want to think about if it were to happen."



Anatomy of a Solar Flare

It helps to understand just what a solar flare is, and how it affects technology. The initial burst from the surface of the sun sends out massive amounts of electromagnetic radiation, particularly x-rays. These travel toward the earth at the speed of light and can cause some problems with communication, but they're typically temporary and not that serious.

Depending on where the eruption is located on the sun, the flare also creates a huge amount of high-energy particles, which can achieve energies in the order of hundreds of millions of electron volts. That's enough to be "very hazardous to spacecraft," says Michael Hesse.

But that's not the worst of it. A solar flare can also shoot out what's called a "corona mass ejection," a stream of particles that moves much slower than the speed of light but still with enough force to cause serious damage.

Typically, this mass hits the earth about one to three days after the initial flare. How fast it gets here depends on the magnitude of the burst, and the faster it goes, the greater the danger. However, not all ejections actually hit the earth. Hesse estimates about one in ten flare ejections impact the earth. The ejection from yesterday's flare will apparently miss.

If a corona ejection is powerful enough, and the earth is in its path, look out. Satellites are the most threatened, for obvious reasons, and a serious flare could damage or even destroy them, Hesse says. For regular people, that could mean no GPS, no satellite TV or radio, and disrupted communications for anything that relies on satellites as part of its network.

The consequences to businesses can be even more severe, as satellites and GPS are intertwined with many other industries. For example, companies use GPS to time-stamp financial transactions.

"Satellites can get irradiated," Hesse explains. "Radiation levels in the magnetosphere can increase substantially, and that can be harmful to satellites. GPS can be substantially affected. Devices will lose lock."

The interaction between the corona ejection and the earth's atmosphere and magnetic field is how solar flares affect the power grid. When those particles hit the ionosphere, they create a voltage between the atmosphere and the earth. As a result, power systems that use the earth as a grounding voltage (read: all of them) no longer work properly, which can disrupt power delivery to large areas.

Earth's atmosphere and magnetic field shield the surface from any direct effects of a solar flare. Generally, terrestrial communication such as cell-phone networks (2G, 3G, and 4G), TV and radio broadcasting, and Wi-Fi aren't affected much by solar storms, if at all. However, if the power grid goes down for extended periods, so too will wireless networks and cell-phone towers. And good luck switching on your TV or radio.

Preparing for the Worst

So how can we prepare for the very real possibility of "the big one"—a colossal solar storm hitting the earth in the next few years? Satellite owners (including the government) can do two things: first, they can harden their birds to be resistant to radiation, which can be expensive. Second, when data suggests a solar flare is about to strike, they can switch off as many systems as possible on the satellites, since typically they're more likely to fail when energized.

Power plants have a much more troublesome dilemma in the event of a major storm. Faced with a potentially massive blackout that could last for days or weeks, they may need to contemplate a rolling, controlled blackout for the duration of a massive solar flare.

"A controlled blackout is much better than a power outage that takes weeks or months," says Hesse. "If you know in advance, you can bring down the load. In the extreme case, it may be the lesser evil. Of course, a decision like that has to based on very, very solid evidence."

The key to having that evidence is refined science in predicting solar flares. While progress is being made, Hesse says predictive models for space weather aren't anywhere near the accuracy of those used for the terrestrial variety.

"I think the National Weather Service does a good job forecasting weather. Space weather is not a mature science. We actually have many things that we don't really understand properly. We're doing a pretty good job, but we need to do more to be able to really say with confidence, 'Tomorrow at this time, it would be a good idea if this satellite system were turned off.'"

Preparing for the Worst

So how can we prepare for the very real possibility of "the big one"—a colossal solar storm hitting the earth in the next few years? Satellite owners (including the government) can do two things: first, they can harden their birds to be resistant to radiation, which can be expensive. Second, when data suggests a solar flare is about to strike, they can switch off as many systems as possible on the satellites, since typically they're more likely to fail when energized.

Power plants have a much more troublesome dilemma in the event of a major storm. Faced with a potentially massive blackout that could last for days or weeks, they may need to contemplate a rolling, controlled blackout for the duration of a massive solar flare.

"A controlled blackout is much better than a power outage that takes weeks or months," says Hesse. "If you know in advance, you can bring down the load. In the extreme case, it may be the lesser evil. Of course, a decision like that has to based on very, very solid evidence."

The key to having that evidence is refined science in predicting solar flares. While progress is being made, Hesse says predictive models for space weather aren't anywhere near the accuracy of those used for the terrestrial variety.

"I think the National Weather Service does a good job forecasting weather. Space weather is not a mature science. We actually have many things that we don't really understand properly. We're doing a pretty good job, but we need to do more to be able to really say with confidence, 'Tomorrow at this time, it would be a good idea if this satellite system were turned off.'"

Auroras a Sure Bet Over Poker Flat


A HUGE solar flare blasted from the sun's surface at 3.1million miles per hour on Monday - and it's heading in our direction.

It sounds like the plot of a blockbuster disaster movie, but here Sun professor Brian Cox explains why there is no need to panic.

THE sun is a giant nuclear reactor the size of a million earths.

It is a giant, violent cauldron of decimated atoms and, occasionally, it has a spot of bad weather.

On Monday the bad weather arrived in magnificent style as a billion tons of superheated matter were blasted into space in a spectacular event known as a solar flare.

Here on earth we won't feel a thing - it is relatively small and the explosion did not point directly at us. If you live in the far north you might see the Northern Lights dancing across the sky as increased numbers of high-energy particles smash into Earth's magnetic field.

Sun Professor ... Brian Cox
Sun Professor ... Brian Cox
The largest solar flare in recent history is known as the Carrington Flare. On September 1, 1859, English astronomer Richard Carrington observed a series of flashes over a group of dark areas on the sun's surface, known as sunspots.

The darkened skies of London were bathed in a spectacular display of the Northern Lights, which are rarely visible from southern Britain. It was said that you could read a newspaper by their light.

But there is a much more threatening side. In 1859 the entire telegraph system failed as powerful electrical currents swept through the wires. Operators got electric shocks and the paper caught fire.

If a Carrington-sized flare hit today, it is thought that a large fraction of the satellites in orbit may be permanently damaged, leading to a communications blackout and potential chaos.

Fortunately, these massive explosions occur only once every 500 years, but this week's little blip serves as a reminder of the power of our nearby, friendly yet threatening star.