This past fall, solar flareslarge jolts of energy from the sun—were forecast to interrupt communication and GPS devices. Nothing happened. In 2006, U.S. government researchers predicted that the next cycle of sunspots, the magnetic regions on the sun that appear as dark spots, would be as much as 50 percent stronger than the previous one, citing a “newly developed [computer] model” boasting “more than 98 percent accuracy.” Instead, that sunspot cycle, in progress now, is on track to be the weakest in nearly a century. Recently, a scientist told CNN that storms on the sun could “bring down satellites … interrupt our power grid,” and cause “trillions of dollars” in damage. Perhaps, but the ponies may be a better wager. And here’s a really scary prediction to worry about: London’s Telegraph newspaper warned in 2010 that solar activity could erase your iPod!
With the world increasingly dependent on electronics, “space weather”—variances in flares and solar wind (charged particles) emitted by the sun—is attracting more attention. Yet despite the possible vulnerability of the modern economy to solar activity, not to mention the simple magnitude of Sol and life’s reliance on it, our knowledge of the star is surprisingly rudimentary. “We are a long way from being able to predict how the sun will behave,” says Daniel Baker, a solar-study specialist who directs the Laboratory for Atmospheric and Space Physics at the University of Colorado.
Researchers think they have a good idea of what happens inside the sun. Hydrogen, the lightest element and the sun’s primary constituent, fuses to become helium, releasing energy. Eventually, long after humanity has gone extinct or evolved into some other form, Sol’s hydrogen will be consumed. Then the helium will begin to fuse into medium-weight elements. An eon after that, the medium-weight elements will begin to fuse into metals. Ultimately Sol will explode, scattering heavy elements into the cosmos. It’s thought that all the heavy elements of the universe were forged within stars that later exploded, supernovas having been more common when the firmament was young. The Earth, your body—both are composed of elements made inside ancient stars that exploded.
Scientists are confident that the sun is in its “main sequence”: it has burned at about the same heat for perhaps a billion years, and it’s likely to stay at about the same rheostat setting for another billion years or so. The numbers involved are staggering. The sun consumes about 600 million tons of hydrogen per second. At that rate, the mass of the Earth would be gone in 70,000 years. Yet Sol so far has exhausted only a small percentage of its energy potential. Though 93 million miles away, the sun shines so fiercely that it dazzles the eyes and makes the skin sting in summertime. And that’s after almost all of its output simply radiates off into the void: for every one unit of solar energy that impacts the Earth, 1.6 billion units do not. Life on Earth depends on the sun’s table scraps.