Superheated plasma bursted from the sun's edge on May 1 in a gigantic rolling wave, said NASA, which published a dazzling video captured by its sun-watching spacecraft.
This solar eruption is known as a coronal mass ejection, or CME, a kind of solar storm on the sun's outer atmosphere that can send electrically charged particles into space. When a CME explodes in our direction, it usually takes three days to arrive. CMEs can occur simultaneously with solar flares, another kind of sun storm involved in releasing energy associated with sunspots.
A large CME can discharge a billion tons of particles into space at several million miles per hour. Solar matter gushes out through the interplanetary medium, hitting any planet or spacecraft along its way.
Like solar flares, CMEs, when directed at the Earth, can generate a space weather event called a geomagnetic storm, which occurs when they interact with the Earth's magnetic envelope for an extended period of time. CMEs at this intensity are unlikely to disrupt electrical systems on the Earth or interfere with GPS or satellite-based communications systems. But they may cause auroras near the poles.
The most powerful Earth-directed CMEs can also imperil astronauts and satellites in orbit, and they can even damage ground-based power infrastructure.
The latest CME, however, took place on the edge of the sun and didn't point at the Earth, said agency officials. The video, taken in extreme ultraviolet light by NASA’s Solar Dynamics Observatory (SDO), shows that the sun's surface emitted a shimmering wave of plasma that splashed into open space. The event lasted two and a half hours.
Launched in 2010, the $850 million SDO satellite has provided detailed views of solar flares, CMEs, and other space weather events in different wavelengths, including the extreme ultraviolet range of the light spectrum used to make the May 1 solar eruption video.
Wednesday's solar explosion was another indication that the sun is reaching the peak of its cycle, which lasts about 11 years. On April 12, the SDO observed an Earth-directed CME, preceded by the most energetic solar flare of the year.
The National Oceanic and Atmospheric Administration experts have predicted that the solar maximum is likely to occur this May.
"But what we’ve come to find is the activity has really toned down over the last couple months," said Alex Young at NASA's Goddard Space Flight Center in a NASA's podcast on Wednesday. "We reached really the peak towards the end of 2011."
Because many of the previous solar cycles actually had two peaks, he believed that another solar maximum is going to happen.
"We’ve reached one of those humps and think that eventually the activity will pick back up and we’ll see another hump, a double hump solar maximum," Young said.
Do scientists expect a huge solar storm in 2013? On its website, NASA says that no current observations or data indicate an imminent solar catastrophe. Scientists believe the intensity of the upcoming solar maximum will be similar to the previous maximum in 2002.