A powerful M2-class solar flare erupts from the sun on Jan. 19, 2012 in this imager from NASA's Solar Dynamics Observatory. 
 
 A powerful flare erupted from the sun Thursday (Jan. 19), unleashing a plasma wave that may supercharge the northern lights for skywatchers in high latitudes this weekend. 
 
 The solar flare occurred at about 11:30 am EST (1600 GMT) and touched off a massive solar explosion — known as a coronal mass ejection — aimed at Earth, space weather experts and officials said. The charged particles from the sun explosion should reach Earth by Saturday night (Jan. 21), and could amp up northern lights displays when they hit the upper atmosphere. 
 
 "Forecasters say strong geomagnetic storms are possible when the cloud arrives during the late hours of Jan. 21st. High-latitude (and possibly middle-latitude) sky watchers should be alert for auroras this weekend," the skywatching website Spaceweather.com announced in an alert. 
 
 Several space telescopes recorded photos and video of the solar flare, including NASA's Solar Dynamics Observatory (SDO) and the Solar Heliospheric Observatory (SOHO). [Photo and video of the solar flare] 
 
 According to the Space Weather Prediction Center maintained by NOAA, Thursday's solar flare erupted from an active sunspot group called Region 1401. Another solar hotspot, called Region 1402, is also fired off a flare, the center reported. 
 
 Auroras occur when charged particles from the sun interact with Earth's upper atmosphere, releasing visible light in the process. The particles are funneled toward Earth's polar regions by the planet's magnetic field, with the northern auroral displays known as the aurora borealis, or northern lights. The southern counterpart is called the aurora australis, or southern lights. 
 
 Thursday's solar flare rated as a powerful M2-class sun storm on the scale used by astronomers to measure flare strength. M-class storms are powerful, but mid-range, types of solar flares. They fall between the weaker C-class flares and the most powerful X-class solar storms, which can pose a threat to satellites and astronauts in orbit, cause widespread communications interference and damage infrastructure on Earth when aimed directly at the planet. 
 
 SDO mission scientists have said that sunspot group 1401 has been unleashing solar flares almost daily as the sun's rotation slowly turned the solar hotspot toward Earth in recent days. On Wednesday (Jan. 18), the region unleashed an M1.7-class solar flare, they said in a Twitter post. 
 
 The sun is currently in the middle of an active phase of its 11-year solar weather cycle. The current sun storm cycle, called Solar Cycle 24, is expected to peak in 2013, NASA scientists have said. 
 
 Editor's note: If you snap an amazing northern lights photo, or other skywatching image, and would like to share it for a possible story or gallery, please contact managing editor Tariq Malik at tmalik@space.com. 
 
 Follow SPACE.com for the latest in space science and exploration news on Twitter @Spacedotcom and on Facebook. ||||| Combined images from NASA's Solar Dynamics Observatory (SDO) and Solar and Heliospheric Observatory (SOHO) satellites show a giant blob of plasma (top) ejected by the sun on Thursday. The cloud of charged gas is expected to reach Earth Sunday. (Courtesy of NASA) 
 
 A huge sunspot unleashed a blob of charged plasma Thursday that space weather watchers predict will blast past the Earth on Sunday. Satellite operators and power companies are keeping a close eye on the incoming cloud, which could distort the Earth’s magnetic field and disrupt radio communications, especially at higher latitudes. 
 
 “Our simulations show potential to pack a good punch to Earth’s near-space environment,” said Antti Pulkkinen of the Space Weather Laboratory at NASA’s Goddard Space Flight Center in Greenbelt. 
 
 But, he added, “We’re not looking at an extreme event here.” 
 
 The front edge of the burst should arrive Sunday morning, said Joseph Kunches, a spokesman for the Space Weather Prediction Center, part of the National Oceanic and Atmospheric Administration in Boulder, Colo. 
 
 “At first glance, it was, ‘Oh my God, it’s at the center of the [sun’s] disk, it ought to go right to the Earth,’ ” Kunches said. But upon further review and “head-scratching” Thursday, NOAA’s space weather team calculated that most of the plasma blob should pass harmlessly over the top of our planet. 
 
 “It’s more of a glancing blow,” Pulkkinen said. 
 
 At their most intense, solar discharges, known as “coronal mass ejections,” can disrupt satellites, radio communications and the power grid, and force airlines to reroute transcontinental flights that pass near the North Pole. Solar activity can also generate dancing auroras, the northern and southern lights. 
 
 Spit out by the sun Thursday morning, the huge blob of charged gas spotted by NASA satellites is speeding toward Earth at more than 2 million mph. The most damaging solar discharges, which are very rare, can zoom at speeds more than twice that fast. 
 
 The ejection appears to be the most threatening since the sun spit out three large blobs in quick succession last August. 
 
 Such discharges shoot out of sunspots, which are dark areas on the sun’s surface where tangled magnetic fields sometimes discharge massive spurts of energy. 
 
 Solar activity ramps up and down on a roughly 11-year cycle. Over the past year, the number of solar flares has jumped up as the sun approaches its predicted maximum activity in 2013. 
 
 While the Earth appears to have dodged this particular solar bullet, the roiling sunspot could generate more activity over the coming week before it rotates out of the view of the Earth. 
 
 “We’re keeping a close eye on it,” Pulkkinen said. 
 
 Besides sparking pretty auroras, heightened solar activity has a more tangible benefit: It cleans up space junk. As the sun acts up, the Earth’s atmosphere expands, increasing friction on dead satellites, rocket parts and other trash in low Earth orbit, pulling them down. 
 
 The amount of debris in Earth orbit “actually decreased during 2011 as solar activity increased toward an anticipated maximum,” NASA’s chief space junk watcher, Nicholas Johnson, wrote in the January issue of the agency’s Orbital Debris Quarterly Newsletter.
– It might pay to glance up at the sky late tonight. A solar flare that erupted from the sun on Thursday is sending a blob of charged gas toward Earth that could make for some dazzling displays of the northern lights, reports Space.com. (The higher latitudes, such as Alaska, will get the best views.) Known as a coronal mass ejection in science-speak, the blast isn't expected to cause much trouble for satellites or the power grid, notes the Washington Post. The site SpaceWeather.com has more details.