Impending solar storm

The end of the 5,126-year long Mayan calendar on December 21, 2012 was interpreted by many as the day Earth would cease to exist. The doomsday of Mayan calendar has come and gone. But the apocalyptic fears for a calamitous end of the world did not materialize. The Earth is still spinning and orbiting the Sun.
However, fears of an Armageddon have been heightened once again after NASA issued a bulletin warning that the Earth could be subjected to a solar storm of biblical proportions this year. If there is a direct hit, the impact could be catastrophic, costing trillions of dollars in damage to our economic and high-tech infrastructures and affecting some hundreds of millions of people. The doomsday believers are once again speculating that fall-out from the ominous solar storm could be the end of our planet.
A solar storm consisting of many solar flares is the most violent form of solar activity. A flare occurs when magnetic energy that has built up in sunspots is suddenly released. First discovered by Galileo in 1610, sunspots are relatively cool, dark floating islands of electromagnetic storms on the surface of the Sun called the photosphere. Near large sunspots, about a hundred flares occur each day. Typical length and width of a flare are 30 and 15 Earths stacked end to end, respectively.
A flare, accompanied by a burst of ultra-high speed protons and electrons, together with X-rays, ultraviolet, and visible radiation, is followed by a colossal amount of coronal mass ejection (CME). The energy packed in a large flare is equivalent to a nuclear explosion magnified a billion-fold! Relax, the entire energy does not reach the Earth; substantial amount is used up in heating the space surrounding the Sun, its corona (a tenuous uppermost layer of the solar atmosphere) and beyond to 100 million degrees Centigrade.
As the flare races toward Earth, its radiation and CME rip through the upper atmosphere and ionize neutral atoms by removing electrons from them. Most CME's take 18 to 30 hours to reach the Earth. Luckily Earth's magnetosphere guards us from the hazards of such outbursts by absorbing the worst of the radiation. Occasionally, charged particles flowing outwards from a CME escape into the solar wind. If the charged solar wind reaches the Earth, electrons in the wind collide with atmospheric atoms and excite them. The atoms quickly de-excite, emitting visible radiation which gives rise to a spectacular display of colors - auroras (borealis or australis) in the sky.
Flares are most common when numerous sunspots are visible on the solar surface. The time interval between waxing and waning of flares, called solar or sunspot cycle is approximately 11 years. The largest solar storm on record occurred in 1859. It was called the Carrington Event, named after the British Astronomer Richard Carrington, the discoverer of solar flares. It bathed "two-thirds of the Earth's skies in a blood-red aurora a night later, and crippled all of global navigation and global communication, such as it was at that time.”
Two recent massive storms that pummeled the Earth are the Great Aurora of March 1989 and the Halloween Sun Storm of October 2003. The “geomagnetic storm” of 1989 blacked out lights for millions of people in Québec, Canada. Its violence marked the prelude to the solar activity cycle that peaked in July 1989. The Halloween storm disabled many satellites and damaged instruments on a Mars orbiter.
Between 2007 and 2009 the number of sunspots was at a minimum and solar activity went into hibernation. There were practically no flares of consequence during this time. The Sun came out of dormancy last year, spewing off numerous powerful flares, but the gigantic one is waiting in the wings for this year.
NASA believes that the size of the impending solar storm will eclipse the Carrington Event. If the storm hits the bull's-eye, it will disrupt everyday life and leave global economy in a bedlam. The energy released by the storm will cripple Earth's technological infrastructure, mess up satellites, radio communications, internet, and navigation signals from GPS satellites, halt aviation and severely damage electric power grids.
So are we going to witness the end of the world this year? The doomsday prophets will once again be disappointed. The thought of a solar Armageddon in 2013 is far-fetched because the thousands of miles thick magnetosphere 40,000 miles above won't fail us. Besides, lot of the CME is faced away from Earth and consequently the danger is lessened. In fact, other than the usual inconveniences caused by solar storms, we will be entertained to a dazzling show of the auroras. Nonetheless, in the future we can expect a monstrous solar storm that would make the Carrington Event look like a rain shower.

The writer is a Professor in the Department of Physics & Engineering Physics, Fordham University, New York.