A song written by Hy Zaret and Lou Singer, later popularized by the band They Might Be Giants, claims that "the sun is a mass of incandescent gas, a gigantic nuclear furnace." Upon closer examination, it appears that this initial classification of the sun is a little too narrow. It turns out that the sun is a complex body that we still don't understand fully.
But here's what we do know: The sun is a massive object comprised of intensely hot, ionized gases. We call this kind of gas plasma and it's the most common state of matter in the universe. The atoms that make up the gases in the sun are so hot that they can't hold on to their electrons. The gases flow in currents through the sun, carrying electrons with them.
If you're familiar with electromagnets, you know that an electrical current can create a magnetic field. That's the case with the sun. The sun has an enormous magnetic field around it. The rotation of the sun perpetuates this magnetic field.
To make matters more complicated, hot objects tend to expand. The sun is an extremely hot object. But the sun is also large and dense, which means it has a strong gravitational pull. The sun's gravity balances out its tendency to expand.
The combination of these forces can cause the sun's surface to change in dramatic and sometimes violent ways. The currents of gas cause magnetic field lines to twist. That can prevent hotter gases from the sun's core from rising to the surface, creating sunspots. Sunspots appear darker than the rest of the sun's surface. They are also cooler than the brighter areas that surround them.
The hot gas trapped beneath sunspots exerts pressure on the magnetic field lines that prevents the gas from reaching the surface. This winds the magnetic field lines into tighter coils. Sometimes, even more field lines become entangled. Once in a while, the magnetic field lines will uncoil without much incident and the sunspot fades as the hot gases rise to the surface. But sometimes the pressure continues to build until the magnetic field lines snap out suddenly, causing a solar flare.
Solar Flares and Coronal Mass Ejections
A solar flare isn't just an explosion of hot gases. It pushes out waves of light all across the spectrum. That includes light we can't see -- including radiation in the form of X-rays and gamma rays. These rays can be dangerous to humans. Fortunately, the Earth's atmosphere absorbs most of these high-energy rays.
That's not to say everyone is in the clear after a solar flare. Humans in space or at high altitudes -- on board an airplane, for example -- could risk exposure to intense radiation. Short-term damage could include skin irritation. Long-term consequences might include an increased risk of developing skin cancer. But it's likely that any affected human would eventually recover from the exposure.
Electronics are also vulnerable to these rays. If high-energy rays were to hit a satellite, they could strip electrons from the metal components, ionizing them. As electrons break free, they could short out the electronics within a satellite. They could also create a magnetic field that would damage the satellite's systems. Some satellites have shielding to protect them from these rays, but many are still vulnerable.
Because our atmosphere absorbs most of these dangerous rays, terrestrial systems are fairly safe from solar flares. But another solar event called a coronal mass ejection (CME) can cause serious problems for electrical systems here on Earth. During a CME, the fluctuations of the sun's magnetic fields cause a large portion of the surface of the sun to expand rapidly, ejecting billions of tons of particles out into space. Sometimes CMEs accompany solar flares -- but not all solar flares produce CMEs and not all CMEs accompany solar flares.
Unlike a solar flare, a CME doesn't produce intense light. But it does produce a magnetic shockwave that extends billions of miles out into space. If Earth is in the path of that shockwave, our planet's magnetic field will react to the event. It's similar to what happens if you put a weak magnet next to a strong one. The weak magnet's field will align itself to the strong magnet's field. A magnetic shockwave from the sun could cause the alignment of the Earth's magnetic field to shift unpredictably.
Pretty lights aren't the only consequence from a CME. The magnetic fluctuations can cause compasses to fail. And since magnetic fields can induce electricity, any conductor could become an inductor. A powerful CME could induce electricity in large, powerful conductors. That could overload electrical systems and cause massive damage.
Next, we'll take a look at exactly how badly off we could be after a massive CME event.
Frying Electronics with the Sun
While a solar flare alone might not be enough to cause problems on Earth's surface, a powerful CME is another story. In fact, massive CMEs have affected the Earth in the past. But we weren't as advanced in electronics, nor did we depend upon them as heavily the last time a CME really smacked us around.
In 1859, an enormous CME caused massive magnetic fluctuations in the Earth's magnetosphere -- the magnetic field surrounding the planet. People living as far south as Cuba witnessed the northern lights phenomenon. Compasses and telegraph systems failed. Scientists and academics debated the cause of all the commotion. We now know it was due to a CME. The CME was so massive that it caused what we call a solar superstorm.
Today, we depend much more heavily upon electronics and electricity than we did in 1859. If a similar solar superstorm were to hit us now, we'd be in trouble. The magnetic forces would induce electricity in any large conductor. That includes power transformers and the power grid itself.
That's not the end of the bad news. The power grid in North America operates at near capacity. It wouldn't be able to handle the increased electrical load from a solar superstorm. Power lines could sag and even snap as a result. Massive power outages could affect much of the continent. The magnetic fluctuations would interfere with radio signals, and communication and satellite systems would collapse as well.
It could take weeks or months to repair the damage. During that time, people would have no way to find out what was going on. Emergency services would face serious challenges. While the magnetic fields would probably not short out individual electronics devices like cell phones or computers, communications systems could fail regionally. In other words, small devices would still work but would lack the services they require to be useful.
It's possible that a CME could even affect your computer and cause glitches. In most cases, a simple reboot would solve the problem. But with the loss of the power grid, you'd be limited by your battery's charge. Once that ran out, you'd be stuck.
There's no way to prevent a solar superstorm but there are steps we can take to limit the impact of a CME. One is to overhaul the power grid system. We need a smart grid that isn't operating so close to capacity as our current grid. We also need to develop shielding to protect our electrical infrastructure from magnetic fluctuations as much as possible.
Even in these worst-case scenarios, the superstorms don't wipe out all electrical systems across the planet. Some regions would remain relatively unaffected. It would require a solar event of unprecedented magnitude to wipe out the electrical systems across the planet. But even a modest CME could demonstrate how vulnerable we are to the sun's magnetic temper tantrums.
Learn more about the sun, magnets and electronics by following the links on the next page.
Related HowStuffWorks Articles
More Great Links
- Beasley, Sandra. "Look at the Sun." American Scholar. Summer 2008. Vol. 77, Issue 3, p. 17.
- Encyclopedia Britannica. "Geomagnetic field." 2009. (Nov. 2, 2009)http://www.library.eb.com/eb/article-9368
- Encyclopedia Britannica. "Solar flare." 2009. (Nov. 2, 2009)http://www.library.eb.com/eb/article-9068560
- Encyclopedia Britannica. "Solar wind." 2009. (Nov. 2, 2009)http://www.library.eb.com/eb/article-9068567
- Encyclopedia Britannica. "Sun." Encyclopedia 2009. (Nov. 2, 2009)http://www.library.eb.com/eb/article-54151
- Odenwald, Sten F. "Bracing for a Solar Superstorm." Scientific American. August 2008. Vol. 299, Issue 2, pp. 80-87.
- Plait, Philip, Ph.D. "Death From the Skies!" New York: Viking. 2008. pp. 33-66.
- Turner, James. "Solar storms ahead: Is Earth prepared?" The Christian Science Monitor. May 6, 2009. pg. 25.