To most people, the sun is a steady, never-changing source of heat and light. But to scientists, it’s a dynamic star, constantly in flux, sending energy out into space. Experts say the sun is now in its most active period in two decades, causing potential disruptions to radio and satellite communications. John Yang speaks with Bill Murtagh of NOAA’s Space Weather Prediction Center to learn more.
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John Yang:
To most of us, the sun is a steady never changing source of heat and light. But to scientists, it's a dynamic star constantly in flux sending energy out into space. Right now experts say it's in its most active period in two decades. For us earthlings the signs of that are likely to be more vivid northern lights or Auroras visible over a wider area of unusual and perhaps disruptions to radio and satellite communications.
The person in charge of coordinating the government's response to these potential disruptions is Bill Murtagh. He's program coordinator for NOAA's Space Weather Prediction Center. So Bill, help us understand this peak activity for the solar cycle help us break that down activity, what's going on? What's the activity?
Bill Murtagh, Program Coordinator, Space Weather Prediction Center:
So the sun is it's like the earth in one way. It's a big magnet, it's got a north pole and a south pole and negative and a positive polarity. But the sun does something a little bit weird over the course of 11 years. It does a reversal of the polarity. The sun is a big ball of electrically charged gas churning and rotating and it sees as this rotation happens to magnetic fields turn and twist.
And essentially they — it's a rotation of that magnetic field over that 11-year period or right in the middle of that, that process, the sunspots emerge. And they're localized magnetic stressed areas and the sun that can produce these big eruptions and when the eruptions occur solar flares, coronal mass ejections, energetic particle events, they all blast material or energy and radiation towards the Earth, and can affect a lot of the different technologies we rely on for everything we do.
And it just happens that right now we're in the very middle of this 11-year reversal process. And we refer to it as solar maximum. So solar maximum peak in that period of most solar activity when we're seeing the most sunspots. So that's exactly what's been happening over the last couple of years and will happen for the next several years is in this period of maximum. We see lots of sunspots and a lots of eruptions that will be affecting some of our technologies here on earth, but of course producing that beautiful northern and southern lights as well.
John Yang:
Are some of these solar maximums more active than others.
Bill Murtagh:
Yes, it's kind of like the hurricane season like some most of us know, some hurricane seasons very active up to 20 hurricanes, others not so much. You could have less than a handful of hurricanes. Same thing with the sunspot cycle. We've got some very big cycles. We've been measuring the sunspot cycles and 1755.
The biggest one was actually solar cycle 19 which peaked in 1953, the last couple of cycles, including this current cycle quite a bit smaller. So they do range in intensity. And indeed, it's 11 years average. But sometimes we see them as quick as like a nine year cycle. Sometimes it's all the way up to about 14 year cycles. So they do vary again, kind of like hurricane seasons.
John Yang:
How do you measure what's going on? How do you track what's going on?
Bill Murtagh:
So, back in the old days, most people sometimes wonder, how would you do this back in 1755? Well, essentially, since Galileo and others invented the telescope, we've been watching the sun, projecting an image of the sign on to a white light board where you can see the sunspots. So we got this continuous record of sunspots, dating all the way back to 1755. So that's a very useful database, that's helps us establish that 11-year, that average 11 year cycle.
But of course, technology has evolved tremendously over the last 20, 3, 40 years. So now we've got all sorts of instruments in space, taking pictures of the sun, monitoring the sun surface, monitoring the corona, and then we've got the in situ the in place measurements, and million miles out in one spacecraft and closer to Earth, we have more instruments measuring the emissions from the sun all the way down to the surface of the Earth, where we have all sorts of instruments, again, measuring different types of, of emissions from the sun, and how they're affecting the technology and the Earth's atmosphere. The Earth's ionosphere.
John Yang:
Tell us more about the practical effects of this on Earth, and then maybe even in space.
Bill Murtagh:
So these are these eruptions can occur when they do occur, there's all sorts of emissions and when the flare occurs as a blast of electromagnetic radiation, it can affect GPS, for example, it can affect satellite communications, aircraft, communicating with the ground can have interference, very degradative communications can happen. We get these big energetic plastic particles that will follow soon after the flare. They can affect satellites. They affect the astronauts in space, which is a big thing going forward, supporting the Artemis missions and going back to the moon and the geomagnetic disturbance, that's really, really important.
Because when the CME, that coronal mass ejection hit search magnetic field, it produces electrical currents, unwanted currency can flow right into the power grid, and cause big problems. And worst case scenario can actually produce a blackout.
So it's one of the big things we have to do on the Space Weather Prediction Center in Boulder is get the alerts and warnings out to the power grid owners and operators across the United States and Canada. So they can take action to ensure we can keep those lights on during these big, big geomagnetic storms.
John Yang:
You're talking about some of these past effects. I mean, I know that some of these records go back all the way to the 18th century. Tell us about that.
Bill Murtagh:
Well, it's been it's just again, I talked about hurricanes earlier. I'll do it again. People know what Hurricane Katrina and Sandy and space weather we've had a big events too. We had what's called the Carrington event in 1859, which was an extraordinary eruption. We have a an astronomer in England, watching the sun leaves doing his little spot drawing and all of a sudden he sees these big white things on his son's drawing. He was looking at a major flare.
And just 19 hours later, that coronal mass ejection made its way to Earth impacted the Earth. And it surprised a lot of people because you know, our friends up in the north and Canada and Alaska, Scandinavia, they're used to seeing the Northern Lights. What was it like in September of 1859, when the folks in Cuba and Central America looked up and could see the northern lights?
So it's kind of a proxy measurement of how intense the magnetic storm was. It was a powerful storm and even the technology of today, the telegraph systems, big long conductors, wires, lines, and induced current when right through those wires causing all sorts of havoc. So it was an extraordinary event and it's the one that we fear today if should it occur today, the consequence could be quite significant.
John Yang:
Bill Murtagh of NOAA's Space Weather Prediction Center. Thank you very much. It's fascinating.
Bill Murtagh:
John has a pleasure talking to you. Thanks.
