The most powerful solar storms in the last five years threatened to wreak havoc with our digital systems on Earth last week. To find out just what solar storms are, why they are in the news recently and why we are more vulnerable to them than ever before, Smart Planet turned to space weather expert Bill Murtagh, program coordinator for the NOAA Space Weather Prediction Center.
SmartPlanet: So what is a solar storm?
Bill Murtagh: Solar storm is loose term to capture the bigger picture of what we call space weather. From the solar flare we get emissions of radiation that affect the Earth environment and then there is an eruption associated with that flare that causes a geomagnetic storm. The whole thing we call a solar storm or space weather.
SP: Are the emissions the coronal mass ejection?
BM: Yes, the coronal mass ejection blasts the billions of tons of plasma that escapes out from the sun sometimes impacting Earth creating geomagnetic storming. This is all part of the solar storm, also known as our space weather.
SP: Presumably other events can be a part of what we call space weather?
BM: From our perspective it is just from the sun. We do get high-energy radiation from deep space. We use the term galactic cosmic radiation, but that doesn’t vary much. It does vary over the 11-year solar cycle but we don’t get pulses and events based on the galactic cosmic radiation. So essentially all the space weather we are interested in has its origin right there, on the sun.
SP: Why do we need to study space weather?
BM: It’s largely because of our reliance on advanced technology for everything we do today. We’ve always had some concern with space weather for as long as we’ve had technology. Back in 1859 we had a big solar flare that impacted the telegraph system of the day.
But consider what has happened on Earth in the last 10 or 15 years. Our reliance on cell phones. Our reliance on GPS, which now pervades society. Our reliance on satellites for so much of what we do. It is these very technologies that are vulnerable to space weather. We have to understand the space environment and understand what we need to do to mitigate the effect of it on the technology we rely on. Because when we lose this technology for any length of time it can be anywhere from a little bit bothersome to bordering catastrophic.
SP: How do we mitigate space weather’s impact?
BM: Well it depends on which sectors are impacted. Take one technology, like aircraft. If you are going to fly from the United States to Asia typically you will fly over the north pole. Last year we had 11,000 flights over the polar regions. The radiation from these solar storms flows in along Earth’s magnetic lines concentrated at the polar regions. And it really impacts the communications of the aircraft and even the navigational systems. So the airlines, when they get the storm warnings, they reroute the flights, and get them away from the polar regions. That’s happened several times over the last couple of days.
SP: How do you measure the seriousness of space weather?
BM: We use a solar radiation scale of 1 through 5, with 5 being extreme. This week we’ve been at the 3-level. And a 3-level radiation storm is a threshold where airlines will reroute flights away from the poles.
SP: Was there anything really that unusual about the storms that happened this week? Or was it just a media frenzy? I don’t recall this much attention being paid to the solar cycle 11 years ago.
BM: Yes, good question. There’s nothing really exceptional about this week’s event. There are three different types of space weather that we measure and we did hit the 3-level on each of the three types with this particular outbreak. Now that is the first time that’s happened during this solar cycle.
But today, as opposed to over a decade ago, we have a whole new media landscape for this cycle, with the web and blogs. So people are just a lot more aware of things that are happening and there is a lot more communication across the globe, period. There has been a lot of attention paid to space weather in the last four or five years.
Because we started looking back at the big events in 1859 and 1921 and recognizing they were much larger than anything we’ve seen in recent history and should one of them occur today the impact could be very significant on the nation. So it’s got the attention of the highest levels of government. Consequently it’s getting a lot more attention.
SP: You mentioned there are three types of space weather? What are the three types?
BM: The first is the R-scale which is the solar flare radio blackouts. The electromagnetic emission from the flare is impacting Earth, at the speed of light. We have 93 million miles from the sun to here, and it takes only 8 minutes to get here and we’d feel certain types of effects. It can impact GPS devices.
Within about an hour or two after that we start looking for particle radiation. We call this our S-scale, the solar radiation scale. This would affect satellites and this is what NASA would be worried about regarding astronaut protection. And it also impacts the airlines.
And the third type of space weather is the geomagnetic storm, the G-scale. Which is caused by the enormous blasts of material from the sun. It usually takes a couple of days before it impacts the Earth. And that is what we had Friday morning, the G-3 conditions, with Aurora Borealis [Northern Lights] visible in the northern states.
SP: NOAA seems to have a long history of studying space weather, you mentioned the 1859 event. How far back do the records go?
BM: It depends on what we are measuring. One of the oldest records, by far, is the sun spot records. If you could look at the sun with a welder’s mask or look at it during sun set you can see sun spots. So even 2,000 years ago the Chinese records make references to sun spots. And we have excellent observations and drawings of sun spots dating back to the 16th Century. Galileo sun spot drawings are kept in the Vatican. So it’s very useful for us to see the sun spot cycles dating back hundreds of years.
We could measure the Earth’s magnetic field back in the mid-19th Century because during that big 1859 storm—we refer to it as the Carrington Flare—we had magnetometers in place at observatories in London that detected the disturbance in the Earth’s magnetic field.
The other big record of these storms and when they occurred is records of the Northern Lights and the southern extent of the Northern Lights. Our friends in Canada and Alaska are used to seeing the Northern Lights, but picture what happened in 1921 with a geomagnetic storm so strong that the Northern Lights were visible in Cuba and Jamaica.
So we have records from the mariners of old who kept the records of weather conditions and sightings of the aurora, so we have a good sense of how strong these storms were, dating back hundreds of years. More modern satellite measurements only date back to the 60s.
SP: And when was the most recent largest geomagnetic storm?
BM: The one in 1989 was the most significant one in the last 50 years. The 1859 and the 1921 were quite a bit stronger than this one. But it was the 1989 one that brought the electric power down in Quebec and caused disturbances as far south as Virginia.
SP: So is it really an exact pattern of an 11-year cycle?
BM: Sometimes that 11-year cycle can mislead people. It’s an 11-year cycle but we only need one rogue group of sun spot activity to cause the potential problems on Earth. Some of the biggest ones occurred in October of 2003, December of 2005 and January 2006. So even four or five years after the maximum peak of the cycle things can happen. There was little actively in 2008 or 2009. Big things can happen anytime over a seven year period.
SP: So the number of solar storms doesn’t necessarily mean more danger? All it takes is one bad storm at any point during the cycle?
BM: Yes, correct.
SP: What causes the 11-year cycle? What causes frequency and what causes severity of the storms? Do we have any idea?
BM: Not really. The differential rotation of the sun and the fact that it’s one big plasma ball. We don’t understand why it’s an 11-year cycle and not 21 or 41 or 51. That is not understood.
SP: Are we curious about that? Or is it not that important?
BM: Well, what we would like to know is the magnitude of the sun spot cycles. One interesting fact when we look back on the historical record. Series of very low sun spot cycles 1640-1715. For 75 years they were practically non-existent. That period happened to coincide with the coldest period of the mini-ice age. So the outputs of the sun being diminished for an extended period will influence climate. How much is the big question.
But we would like to know if that could happen within the next 50 years. We’d like to be able to predict when the cycles will be big or small.
SP: What can you predict today?
BM: When I look at the sun today and point to a narrow sun spot group we know there is potential for eruption. We have ways of measuring that sun spot group and its complexity and I can put out a prediction indicating a 60 or 70 percent chance of a big flare.
What is missing is that we cannot tell from the sun spot if it will be a big solar flare or not. So I can’t give immediate warning of a flare. Now the other two types of space weather, yes I can provide some warning but all I can give is some probabilistic warning, based on the size of sun spots, that something is likely.
SP: It’s a good thing the sun is so far away then.
BM: Yes we have that 93 million mile distance and over time we have fortunately developed the Earth’s magnetic field and it and our atmosphere provides tremendous shelter from this harmful radiation.
SP: All of this reminds me of our vulnerability to terrorist attacks in the form of a nuclear explosion in the atmosphere just above the U.S.
BM: A nuclear device detonated in space above us could be a very significant thing. Could have a much bigger consequence than one detonated downtown in a city. Because of what that electromagnetic pulse does to our technology would be very significant. There are three phases of pulsing from such a nuclear device detonated in space. And the sort of emissions that would be emitted are the key emissions that we don’t get from the sun down here on Earth. Those would knock out our sensitive electronics here. Over the U.S. it could impact all sorts of systems. The third emission is somewhat similar to the impact from a geomagnetic storm. But from the sun’s emissions we do not have to build those cages and lead shields to protect our data equipment. Our electrical grid may be vulnerable to the sun. But we are not going to see the same kind of pulse that we can see from a nuclear device detonated over the country.