Strong solar storm surprise scientists delivers colorful auroras

March 2015 – SOLAR WATCH – Two bursts of charged matter that spewed from the sun’s surface Sunday were forecast to sideswipe the Earth with minor solar winds late Tuesday night. Instead, they arrived in the morning as a severe solar storm that created dramatic shows of the Northern Lights expected to continue into early Wednesday, potentially as far south as Baltimore. A solar storm rated a four on a scale of five arrived at 10 a.m. eastern time Tuesday, lighting up the pre-dawn skies in the northern United States with the aurora borealis and creating concerns of power grid disruptions and GPS interference, though no major problems were reported. The auroras were spotted around the globe, and if the solar storm’s strength held up, were expected to be visible unusually far south across the United States.

The colorful phenomenon occurs when the energized particles bombard Earth’s atmosphere, exciting the oxygen and nitrogen atoms so much that they give off energy in the form of brilliantly hued light. But what surprised scientists is how much they underestimated the storm even though they acknowledge they know little about what happens between when a solar flare bursts from the sun’s surface and when the energized matter is detected by a satellite about an hour before it washes over the planet. “Our models showed we were just going to receive a glancing blow from this cloud coming off the sun,” said Thomas Berger, director of the Space Weather Prediction Center, a branch of the National Weather Service. “We are now thinking we caught more than just a glancing blow.”

 Scientists had based their forecasts on observations Sunday of two coronal mass ejections from the right edge of the sun as seen from Earth. The events spew plasma from the sun’s corona, a halo of speeding protons and electrons that is hundreds of times hotter than the sun’s surface, into space. But since then, the two clouds of charged particles appear to have merged and intensified, arriving about 15 hours earlier than expected, scientists at the space weather center said. The storm was the strongest to affect Earth since late 2013 and one of two storms rated “severe” in the current cycle of solar activity that started in 2008, they said. The storm was slow to weaken Tuesday, and space weather forecasters said they expected it to continue for 12 hours, with lingering effects for 24 hours to 36 hours. –Baltimore Sun