Fears of disruption as solar storm strikes the Earth
Prof Cally from Monash University in Australia explains what will happen when the solar storm hits
The Earth is being battered by a storm of charged particles from the Sun, which could disrupt power grids, satellite navigation and plane routes.
This solar storm is the largest in five years – and will bombard the Earth’s magnetic field throughout Thursday.
It was triggered by a pair of strong solar flares earlier this week.
The storm was predicted to peak in the afternoon UK time, but experts warn that the Sun’s surface is still active and could trigger further storms.
Activity near the Sun’s surface rises and falls through an 11-year cycle that is due to peak in 2013 or 2014.
Some solar flares result in what is known as a coronal mass ejection (CME) – the launch of a huge bubble of charged particles hurtling toward the Earth at speeds up to millions of kilometres per hour.
As the Sun’s activity has risen in recent months, more such CMEs have occurred.
The Earth’s magnetic field protects it from the constant onslaught of high-energy particles from the Sun and elsewhere in the cosmos.
However, the solar storms that mark the arrival of CMEs can disrupt the field enough to have an effect on the Earth’s surface – causing current spikes in power grids or disrupting navigation devices.
Among the more benign effects is that the magnetic field disturbance can make the Northern Lights may be visible at lower latitudes.
But it is often unclear, even up to the last minute, just how grave or spectacular the effects will be on Earth.
The current CME – travelling at some 1,300 kilometres per second – began arriving at Earth on Thursday morning, and will begin to dissipate into the evening.
David Kerridge, director of geoscience research at the British Geological Survey, said that the storm is not currently as bad as it might have been.
“The magnetic field in the solar wind is not facing in the direction of danger. But it could change, into the early evening,” he told BBC News.
“The part of the Sun where this came from is still active; it’s a 27-day cycle and we’re right in the middle of it, so it is coming straight at us and will be for a few days yet. We could see more material,” he explained.
But regardless of its eventual extent, this episode of solar activity is a preview of the what is to come in the broader, 11-year solar cycle.
Dr Craig Underwood, from the Surrey Space Centre, UK, said: “The event is the largest for several years, but it is not in the most severe class. We may expect more storms of this kind and perhaps much more severe ones in the next year or so as we approach solar maximum.
“Such events act as a wake-up call as to how our modern western lifestyles are utterly dependent on space technology and national power grid infrastructure.”
Many storms are benign; this storm could enable skywatchers to see the northern lights from parts of the northern US and northern UK.
But the strongest storms can have other, more significant effects.
In 1972, a geomagnetic storm provoked by a solar flare knocked out long-distance telephone communication across the US state of Illinois.
And in 1989, another disturbance plunged six million people into darkness across the Canadian province of Quebec.
There are concerns over the potential communication problems for aircraft and disruption to GPS signals caused by current solar activity.
- The sudden release of magnetic energy stored in the Sun’s atmosphere can cause a bright flare
- This can also release bursts of charged particles into space
- These solar “eruptions” are known as coronal mass ejections, or CMEs
- When headed in our direction, the charged gas collides with the magnetic “sheath” around Earth
- The subsequent disturbances in the Earth’s magnetic envelope are called solar storms
- They can interfere with technology: satellites, electrical grids and communications systems
- They can also cause aurorae – northern and southern lights – to be seen at lower latitudes