Northern Lights Ireland: Why are we seeing them more often and when will they be visible again?

The Northern Lights put on a show for Ireland on Thursday but when will we be able to see them again?

Northern Lights over Prosperous in Co Kildare. Photograph: Paul Murtagh

What exactly are the Northern Lights?

The Northern Lights, also known as aurora borealis, are the results of collisions between gas particles in our atmosphere and charged particles ejected from the sun’s atmosphere. The colour of the Northern Lights change due to the type of gas particles that are colliding.

Oxygen molecules at approximately 100km above the earth produce a greenish-yellow colour, while a red aurora can be seen when high-level oxygen molecules are involved. Blue or purple auroras indicate the presence of nitrogen molecules.

Was it known in advance that the Northern Lights would be seen on Thursday night?

Frances McCarthy, education officer at MTU’s Blackrock Castle Observatory in Cork, said it was predicted based on images of the sun that showed a “coronal mass ejection”, where a large amount of the outer part of the sun’s atmosphere was ejected into space.

“When the charged material from the sun arrived yesterday, it affected the upper atmosphere near the poles and made the glow of the aurora,” she said.

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“We saw red light in Cork, due to oxygen at the upper levels glowing. Red aurora are rare. The green light was from lower level atmospheric gases, and are more common. Prior to this, I had only ever seen green aurora.”

The UK’s Met Office had also reported that sightings of the Northern Lights were likely on Thursday night and the early hours of Friday across northern areas of the UK.

Why are we seeing the Northern Lights more frequently and, in particular, so far south in Ireland?

Solar activity changes in an 11-year cycle and we are currently near the top of the cycle of most activity, so eruptions such as coronal mass ejections and sunspots are more common.

Ms McCarthy added that the sun was “last this active in 1989” while aurora are more common near the north and south magnetic poles so only very strong space weather events will affect us or be visible to us as aurora.

Where is the best place to see the Northern Lights in Ireland?

The Northern Lights are best observed in locations with very small amounts of light pollution and clear skies in terms of ideal weather conditions. Parts of the west and north coast offer the greatest chance of seeing the display, according to Met Éireann.

It points out there are a number of forecast services for the Northern Lights; including one which comes from the National Oceanic and Atmospheric Administration (NOAA) that provides a 30-minute forecast for the aurora.

People can also check out spaceweather.com.

Will we get to witness the Northern Lights on Friday night?

Unfortunately no, we are not likely to see the Northern Lights again on Friday night as the geomagnetic storm is subsiding. Ms McCarthy added there would be chances again in the future to see the Northern Lights but probably not this weekend.

Sarah Burns

Sarah Burns

Sarah Burns is a reporter for The Irish Times