Eoin CarleyOn December 23, when Santa is busy preparing yet another round-the-world Christmas flight, something sinister could be brewing on the surface of the Sun.
Our nearest star is becoming extremely active, and this winter it may produce something even Santa should be worried about -- a solar storm.
The storm starts with a sudden burst of energy and an eruption of billions of tons of super-hot gas into space, travelling toward Earth at over 1.6 million kms per hour.
If it were to arrive on Christmas Eve, we have only one question on our minds: while Santa is flying through the atmosphere, will he be safe?
Fortunately, solar physicists have the tools to answer this question. We have been studying the Sun and its effects on Earth for decades now.
State-of-the-art satellites, supercomputers and the latest advances in astrophysics allow us to predict when solar storms will happen and how damaging they will be to Earth and its surroundings.
We know that solar storms can knock out communications satellites and bring down electricity grids.
We also know that the very hot gas and particles of solar storms are dangerous for anything (even reindeer) flying through the atmosphere.
However, Santa should not have much cause for alarm. Being well used to navigating the entire globe, he will know that his main guidance for his journey and his protection during high-altitude flights is the Earth's magnetic field.
This magnetic field, much the same as a giant bar magnet, acts like a protective cushion against these violent solar storms.
The huge amounts of material thrown towards the Earth by the Sun often impact and buffet the field.
It bears the brunt of this impact and prevents the hot gas and damaging particles from breaking into our atmosphere where it may cause us harm.
In fact, the only place where particles manage to reach low into our atmosphere is where the field points directly into the Earth -- the North Pole.
Santa must ensure he spends as little time as possible at the North Pole if a solar storm impacts our planet. Fortunately, most of his journey is at lower latitudes, including Ireland, where we are under the protective canopy of the magnetic field.
The only effect Santa may notice is the needle in his compass dancing around as the field fights hard to keep the solar storm at bay.
Santa and his reindeer will feel no other effects of the cosmic collision occurring above their heads.
However, on his return to the North Pole he will see one of the most beautiful effects caused by solar storms: the shimmering green light of the Aurora Borealis, slowly waving across the Christmas night sky.
If we're lucky, Ireland may see it too.
QEoin Carley is Irish Research Council PhD student at the School of Physics, Trinity College Dublin, and first author on a recent paper on solar storms, published in the prestigious science journal, 'Nature Physics'