NASA's newest telescope is giving scientists their clearest pictures yet of the sun's atmosphere, and in doing so could help mitigate the potentially devastating effects an extreme solar storm could have on our power and communications networks on Earth.
Launched a month ago, the Interface Region Imaging Spectrograph, or IRIS, on Thursday sent some of its first images of the sun back to Earth. The pictures should help scientists form a better understanding of the sun's weather, which is important because its influence on Earth goes well beyond providing sunlight and warmth.
An ever-changing pattern of instability on the sun's surface causes particles to be thrown outward, sometimes directly toward the Earth. These eruptions can take the form of solar flares, which cause the awe-inspiring northern lights, but can also cause the Earth's atmosphere to expand and increase the amount of drag on low-Earth-orbit satellites, such as those used for spying and GPS navigation, shortening their lifespan.
The most violent eruptions can have a much larger impact, including potentially knocking power grids offline and leaving millions without electricity. Such an eruption occurred in 1859, frying parts of the international telegraph system, which at the time was the main medium for long-distance communications.
If such an event occurred today, with electricity and Internet communications such a fundamental part of daily life, it's hard to even fully imagine the potential impact. A recent report from Lloyds of London suggested the damage from a violent eruption could leave 20 million people without power for as long as two years.
All solar weather travels through the lower solar atmosphere, and IRIS contains a powerful spectrograph that will focus on this region of the sun. Thus, scientists hope IRIS will give them a better understanding of these solar events and perhaps help them find a way to predict them.
"These beautiful images from IRIS are going to help us understand how the sun's lower atmosphere might power a host of events around the sun," Adrian Daw, mission scientist for IRIS at NASA's Goddard Space Flight Center, said in a statement. "Any time you look at something in more detail than has ever been seen before, it opens up new doors to understanding. There's always that potential element of surprise."
The Earth is prone to the impact of solar weather because the particles hitting Earth from the sun are magnetized.
"When that magnetic field hits the Earth's magnetic field, we have two magnetic fields interacting and you create electrical currents," said Karel Schrijver, a senior fellow at Lockheed Martin Space Systems' advanced technology center in Palo Alto, California. Lockheed Martin built the spectrograph that lies at the heart of IRIS' observations of the sun.
The electrical currents will run through any conductor on Earth, Schrijver said, and have their greatest effect on high-voltage power lines that sit at the heart of the electric grid. The lines are like inter-city freeways for electricity, carrying power across vast distances at voltages as high as 765,000 volts. Large transformers are used to "step down" the voltage where the lines connect with regional distribution systems, and it is those transformers that are at risk. If the geomagnetic storm is large enough, the induced currents can melt the transformers.
One of the strongest major storms in recent memory occurred in March 1989. Over a period of several minutes, the Hydro Quebec power grid in eastern Canada collapsed and 6 million customers lost power. The blackout lasted almost nine hours and caused an estimated C$2 billion in economic losses -- and it could have been worse. The effects almost cascaded to regional power grids, which could have blacked out the Northeast and mid-Atlantic regions of the U.S.
Scientists and power grid operators worry about the prospect of something much larger, and such an event would not be without precedent.
Over the final days of August and first days of September 1859, an extreme solar storm occurred that ranks as the strongest ever recorded. It enabled amateur astronomers to make the first-ever observations of solar flares, and such giant storms are now named after one of those astronomers, Richard Carrington.
The Carrington event was so strong that aurorae, usually confined to the far north, could be seen in the night sky as far south as the Caribbean. Electricity still wasn't widely in use, but the storm shut down parts of the international telegraph network. In some places, telegraph lines were reported to be sparking, and The New York Times reported from Montreal that the Canadian Telegraph Co. took five hours to send a 400-word report because of the bad conditions.
"So completely were the wires under the influence of the Aurora Borealis, it was found utterly impossible to communicate between the telegraph stations, and the line was closed for the night," the newspaper reported on Aug. 30, 1859.
Historical records suggest Carrington-level events occur every 50 to 250 years, so Earth is now at the 150-year sweetspot for a repeat.
A recent report by Lloyd's of London predicted that another Carrington-level event is "almost inevitable in the near future" and paints a concerning picture of its potential effects. Should the U.S. be hit head on by such a storm, the report says, 20 million to 40 million people could be left without power for anything between 16 days and two years. The recovery time is so long because high-voltage transformers are such specialty items. Power utilities don't keep spare ones lying around, and they take up to 16 months to build.
The economic impact of such an event could be as high as US$2.6 trillion, the Lloyds report said.
The power industry isn't ignoring the threat. An April 2011 workshop between electricity grid operators from the U.S. and Canada resulted in the creation of a space weather alert system for the industry, and plans for coordination should a major geomagnetic storm be detected. Grid operators would have between 15 hours and two days to prepare for the storm by increasing reserves, reducing power transfers and lightening the load on susceptible equipment.
But any reduction in the availability of power could itself have an economic impact, so it's a situation to be avoided unless the likelihood of serious damage to the power grid is high.
Learning more about the sun's weather can only help scientists to provide warnings for such events.
"What we don't know is how it works, what in detail it will damage, or how likely it is that that damage will spread," Schrijver said. "And the difficulty with it is that these things happen only rarely. Once a century is when a really big solar event occurs, and our technological infrastructure has changed so much, we've never been exposed to it."
Martyn Williams covers mobile telecoms, Silicon Valley and general technology breaking news for The IDG News Service. Follow Martyn on Twitter at @martyn_williams. Martyn's e-mail address is [email protected]