Northern Lights moving south to provide spectacular night-time sight

The spectacular Northern Lights may become visible tonight following powerful solar flares on the sun's surface. The weather might even co-operate, according to forecasts from Met ╔ireann.

The lights were seen last weekend and earlier this week as far south as Nice in Europe and North Carolina in the US. Observers here spotted them from both Dublin and Co Wexford.

"I saw it a few nights ago," stated Dr Ian Elliott, solar physicist and former assistant professor at the Dublin Institute for Advanced Studies. "I went out at midnight and despite the glow over Dublin, I saw red streamers overhead and green streamers to the north-east, ray-like things. It is always very subtle and they change all the time."

Also known as the aurora borealis, the lights are more likely to occur when the sun is most active during its "solar maximum". This occurs over an 11- year cycle, one of which we have just passed. The sun at this time is susceptible to solar storms and spectacular solar mass ejections. These involve a tremendous discharge of ionised particles which spew out into the solar system.

If the particles are headed in our direction, they follow the Earth's magnetic field lines, which direct the ionised particles towards the two magnetic poles, Dr Elliott explained.

There they "excite" oxygen and nitrogen in the upper atmosphere, causing them to release photons of multi-coloured light which we see as the beautiful Northern Lights.

The lights should easily be visible in these latitudes if the sky remained clear, he said.

"The most important thing is to get away from city lights so you have a clear view of the northern sky and there is no point going out unless there is an auroral alert."

This alert has come following two coronal mass ejections earlier this week and the signs suggest some of the particles will strike the atmosphere tonight.

Last night's view was largely obscured by cloud cover but tonight "holds a bit more promise", according to a Met ╔ireann forecaster. There should be good breaks in the clouds giving an opportunity to catch them.

"Once one has come, the interplanetary conditions are right for another one to come," Dr Elliott said. The expanding cloud of particles was expected to hit us yesterday or today, with a strong possibility of the aurora borealis delivering a wonderful show tonight.