NASA | SDO Sees Two Solar Flares (by NASA Goddard)

Sun Emits 3 X-class Flares in 2 Days

On June 11, 2014, the sun erupted with its third X-class flare in two days. The flare was classified as an X1.0 and it peaked at 5:06 a.m. EDT.  Images of the flare were captured by NASA's Solar Dynamics Observatory. All three flares originated from an active region on the sun that recently rotated into view over the left limb of the sun. 

To see how this event may affect Earth, please visit NOAA's Space Weather Prediction Center at http://spaceweather.gov, the U.S. government's official source for space weather forecasts, alerts, watches and warnings. {x}

ScienceCasts: Solar Max Double Peaked.

By Kenneth Chang, NY Times, March 18, 2013 In 1859 the Sun erupted, and on Earth wires shot off sparks that shocked telegraph operators and set their paper on fire.

It was the biggest geomagnetic storm in recorded history. The Sun hurled billions of tons of electrons and protons whizzing toward Earth, and when those particles slammed into the planet's magnetic field they created spectacular auroras of red, green and purple in the night skies--along with powerful currents of electricity that flowed out of the ground into the wires, overloading the circuits.

If such a storm struck in the 21st century, much more than paper and wires would be at risk. Some telecommunications satellites high above Earth would be disabled. GPS signals would be scrambled. And the surge of electricity from the ground would threaten electrical grids, perhaps plunging a continent or two into darkness.

Scientists say it is impossible to predict when the next monster solar storm will erupt--and equally important, whether Earth will lie in its path. What they do know is that with more sunspots come more storms, and this fall the Sun is set to reach the crest of its 11-year sunspot cycle.

Sunspots are regions of turbulent magnetic fields where solar flares originate. Their ebb and flow have been observed for centuries, but only in the past few decades have solar scientists figured out that magnetic fields within the spots can unleash the bright bursts of light called solar flares and the giant eruptions of charged particles known as coronal mass ejections.

Experts are divided on the earthly consequences of a cataclysmic solar eruption, known as a Carrington event, for the British amateur astronomer who documented the 1859 storm.

A continentwide blackout would affect many millions of people, "but it's manageable," said John Moura of the North American Electric Reliability Corporation, a nonprofit group founded by utilities to help manage the power grid. Most of the grid could be brought back online within a week or so, he said.

Others are more pessimistic. They worry that a huge and well-aimed eruption from the Sun would cause not only the lights to go out, but would also damage transformers and other critical components of the grid.

Some places could be without power for months, and "chronic shortages for multiple years are possible," according to the National Research Council, the research arm of the National Academy of Sciences.

Still, this sunspot cycle has been quieter than most. And even if the Sun unleashes a huge burst, as it did last July, the odds are that it will head harmlessly in some other direction into the solar system. Only rarely does a giant solar blast fly directly at Earth.

Yet just as a hurricane-fueled surge hitting New York City at high tide during a full moon is rare, rare is not impossible.

"There's always the chance of a big storm, and the potential consequences of a big storm has everyone on the edge of their seats," said William Murtagh, program coordinator for the Space Weather Prediction Center, part of the National Oceanic and Atmospheric Administration.

The most studied, unambiguous example of the Sun's ability to snarl power grids occurred on March 13, 1989, in Quebec. In the early-morning hours, a solar storm generated currents in the transmission wires, tripping circuit breakers. Within minutes, a blackout stretched across the province, shutting down businesses, schools, airports and subways until power was restored later that day.

Canada was hit again a few months later, when another solar storm was blamed for computers shutting down at the Toronto Stock Exchange, halting trading.

The dangers will not go away after the so-called solar maximum--the period of heaviest solar weather--has passed. Even when quiet, with few sunspots, the Sun can still produce a giant eruption.

Solar flares, traveling at the speed of light, arrive at Earth in less than 8.5 minutes and can drown out some radio communications. But it is the coronal mass ejections--in which billions of tons of electrons and protons are disgorged from the Sun and accelerate to more than a million miles per hour--that cause more worry.

The particles, which generally take two or three days to travel the 93 million miles from the Sun to Earth, never hit the surface; the planet's magnetic field pushes them aside.

But then they are trapped in the field. The back-and-forth sloshing generates new magnetic fields, mostly over the night side, and they, in turn, induce electrical currents in the ground. Those currents surge out of the ground and into the electrical transmission lines.