Monday, February 3rd 2020, 8:45 pm - A new study highlights the risks to our technologies and power grids due to intense space weather
Powerful solar storms pose a great danger to our technologies here on Earth, and space weather scientists just determined that we see these storms far more often than we thought, possibly up to once every 25 years.
In September of 1859, while observering sunspots with his telescope, astronomer Richard Carrington witnessed what is still considered to be the most powerful solar flare ever seen. Just days later, the event was followed by intense auroral displays that were visible all the way to the equator. Long distance telegraph lines became so charged with electricity that operators suffered shocks, and for days after they could even send messages without hooking the system up to a power source. In the aftermath, Carrington linked the events, effectively discovering 'space weather' for the very first time.
Decades later, in July of 2012, satellites observing the Sun spotted an immense cloud of plasma - a coronal mass ejection - erupting into space. Detailed computer modelling revealed that if this rapidly expanding cloud had erupted just two weeks earlier, it would have scored a direct hit on Earth, causing another "Carrington-level" solar storm. Lloyds of London performed a study that showed, based on the impacts of the Carrington Event, if Earth had taken a direct hit from the 2012 solar storm, it would have caused world-wide blackouts and satellite failures, with a pricetag to the global economy totalling in the trillions of dollars.
Even now, nearly eight years after the event, it is possible some parts of the world would have still been trying to recover.
These two events are excellent examples of just how dangerous space weather can be, and a new study performed by scientists with the University of Warwick and the British Antarctic Survey now shows that solar storms severe enough to impact our technologies can occur as often as once every 25 years.
"Our research shows that a super-storm can happen more often than we thought," Richard Horne, a space weather researcher at the British Antarctic Survey who co-authored the paper, said in an American Geophysical Union blog post. "Don't be misled by the stats. It can happen any time. We simply don't know when, and right now we can’t predict when."
Our Sun is an active star. It constantly emits a stream of charged solar particles into space that we call the solar wind. Meanwhile, every 11 years, the Sun goes through a cycle of increasing and then decreasing number of sunspots. The more sunspots there are, the greater the chances we'll see intense solar flares, and eruptions of immense clouds of magnetized plasma that are often called 'solar storms'.
We on Earth are largely protected from all of this activity due to our planet's atmosphere and geomagnetic field. An invisible field that is produced by the molten metal core, the Earth's geomagnetic field causes most of the charged particles from the solar wind and solar storms to flow around the planet. Some particles that do make it down into our atmosphere produce the auroras - the Northern and Southern Lights - as they smack into air molecules, causing them to emit light.
Credit: Canadian Space Agency
While auroras are beautiful, there is a dark side to all of this. The same conditions that produce auroras cause disruptions to Earth's geomagnetic field. As the magnetic field fluctuates during these disruptions, it can set up electric currents through the ground that interfere with transmission lines and power grids.
An excellent example of this is the March 13, 1989 Quebec Blackout, which was caused by a powerful geomagnetic storm that resulted from a solar storm that erupted from the Sun just three days before. According to NASA, "the currents found a weakness in the electrical power grid of Quebec. In less than 2 minutes, the entire Quebec power grid lost power." The blackout lasted for 12 hours, and there were even impacts on satellites, as well as the Space Shuttle Discovery, which was in space to deliver a communication satellite into orbit.
This map shows an artist's impression of the extent of the auroras seen on the night of March 12, 1989, and the extent of the resulting blackout over Quebec and surrounding areas, all caused by a geomagnetic storm. Credit: NASA
The denser, hotter and faster the solar storm, the more severe the impacts will be here on Earth - auroras become brighter and visible farther away from the poles, and the greater the disruption will be to Earth's geomagnetic field. The exact results of this depend on specific combination of density, energy and speed, but also on the strength and direction of the magnetic field carried by the solar storm. Thus, we do not always see the same impacts from the same level of solar storm, and they do not always result in blackouts and the like.
The advancing and spreading of technologies across the planet also has an effect on the impacts of any particular solar storm. 150 years ago, during the Carrington Event, the most advanced technology at the time was the telegraph network and it suffered severe and bizarre impacts. Today, there is far more technology spread around the world, and we are far more dependent on it, which potentially makes us more vulnerable to the impacts of solar storms.