Dazzling Northern Lights Display Possible This Weekend (SPACE.com)

The first wave in a volley of solar storm particles from the sun hit Earth Friday (Sept. 9), setting the stage for what could be a striking weekend light show for observers at high latitudes in the Northern Hemisphere, skywatching experts say.

The charged solar particles were expelled by the sun during a series of sun eruptions (called coronal mass ejections, or CMEs) this week. They arrived at Earth Friday, were funneled toward the poles by the planet's magnetic field and began interacting with the upper atmosphere in what scientists call a geomagnetic storm.

That interaction, when solar particles hit bits of the atmosphere and cause them to glow, can create spectacular northern lights displays, also known the aurora borealis. [Amazing Aurora Photos of Summer 2011]

"This could be the first of several hits from a series of CMEs to reach Earth during the weekend," the space weather and skywatching website Spaceweather.com wrote in an alert. "High-altitude sky watchers should b e alert for auroras after nightfall."

The sun erupted with three major solar storms this week between Sept. 5 and Sept 7. The third and largest of the storms was an X2-class solar flare, placing among the strongest types of storms the sun experiences. The coronal mass ejections from the flares were not aimed directly at Earth, so they were not expected to interfere with satellites, power grids or other infrastructure, space weather experts said.

Major solar flares have already created dazzling northern lights for skywatchers throughout this summer. In August, a series of solar events set the stage for an amazing weekend display, according to some observers.

On Aug. 5, skywatcher and photographer Colin Chatfield witnessed an impressive aurora display just outside Saskatoon in Saskatchewan, Canada.

"We don't actually see the aurora too often here, even though we are more north than lots of your audience," Chatfield told SPACE.com in an email, adding that while this year's auroras were a bit dimmer than those of August 2010, he did manage to catch a meteor streaking across the sky this time. "Even though the ones [on Aug. 5] were not as impressive as last year, they were still amazing to watch them develop, then dance overhead."

Editor's Note: If you snap an amazing photo of the northern lights displays this weekend and would like to share it with SPACE.com for a possible story or image gallery, please contact managing editor Tariq Malik at: tmalik@space.com.

You can follow SPACE.com Managing Editor Tariq Malik on Twitter @tariqjmalik. Follow SPACE.com for the latest in space science and exploration news on Twitter @Spacedotcom and on Facebook.

View the original article here

Solstice Sun Storm May Spark Dazzling Northern Lights Today (SPACE.com)

A wave of sun particles unleashed during a strong solar flare this week is arriving at Earth today (June 24) and could touch off a dazzling northern lights display, NASA officials say.

The solar storm occurred Tuesday, June 21, during Earth's solstice, which marked the first day of summer in the Northern Hemisphere and the start of winter in the Southern Hemisphere.

The storm triggered a powerful explosion on the sun, called a coronal mass ejection, which sent a vast wave of solar particles directly at Earth at a speed of about 1.4 million mph (2.3 million kph). Those particles are now buffeting Earth's magnetic field in interactions that could amplify the planet's polar auroras, also known as the northern and southern lights.

"High-latitude sky watchers should be alert for auroras," officials with NASA's Goddard Space Center said in an update today. [Auroras Dazzle Northern Observers]

Supercharged auroras

Auroras occur when solar wind particles collide with atoms of oxygen and nitrogen in Earth's upper atmosphere. The interaction excites the atoms, which then emit light (the aurora) as they return to their normal energy level. [Video: Fantastic Aurora at Earth's Poles]

Tuesday's solar flare registered as a class C7.7 flare (C-class flares are the weakest types of flares), but lasted for several hours. There are three classes of solar flares. M-class solar flares are medium-strength flares, while the most intense solar storms register as X-class flares.

There is a 30 percent to 35 percent chance of a minor geomagnetic storm in Earth's atmosphere today from this week's storm, NASA officials said.

The active sun

This week's solar flare was detected by the space-based Solar and Heliospheric Observatory (SOHO) operated by NASA and the European Space Agency. It came just weeks after another strong solar flare on June 7, which unleashed a massive coronal mass ejection that stunned astronomers with its intensity.

The June 7 event  kicked up a wave of plasma that rained back down on the sun over an area 75 times the width of Earth. The leading edge of the particles that erupted from the sun were traveling at about 3.5 million mph (5.7 million kph), SOHO officials have said.

Another coronal mass ejection on June 14 unleashed an eerie wave of material that formed a partial halo as it expanded into space.

The most severe solar storms, when aimed at Earth, can pose a danger to astronauts in space, satellites and even ground-based communications and power systems. This week's solar flare, however, is not powerful enough to pose a serious risk, NASA officials said.

The sun is currently in an active period of its 11-year solar cycle. NASA and other space and weather agencies are keeping a close watch on the sun using space-based observatories, satellites and ground-based monitoring systems.

You can follow SPACE.com Managing Editor Tariq Malik on Twitter @tariqjmalik. Follow SPACE.com for the latest in space science and exploration news on Twitter @Spacedotcom and on Facebook.

View the original article here