MARGARET WARNER: One of the most powerful geomagnetic storms on record hit the earth today at 1:13 a.m., Eastern Time. It disrupted some airline and space satellite communications and led some electrical grids to curb their power transmissions as a precaution. The storm was triggered by a giant eruption on the sun's surface, known as a solar flare.
Here to tell us about the storm and the solar flare that triggered it is Robert Roy Britt, lead science writer for Space.com.
And Rob, welcome. Start us from the beginning here back to yesterday when scientists noticed an unusual event on the sun's surface. What happened?
ROBERT ROY BRITT: Well, there's these giant sun spots on the Sun. And there's several right now and a couple of them are as big as Jupiter. They are huge. And the sun spots are areas where the suns magnetic energy gets all twisted up and it's -- it puts sort of a cap on the solar energy that's trying to get out of the Sun. It's a bit like a loose cap on a soda bottle and sooner or later that cap's going to blow off and this material is going to come flying out. That is what happened yesterday.
MARGARET WARNER: And so is that what a solar flare is, is this huge eruption?
ROBERT ROY BRITT: Yes. It's a little bit complex. You have initially a solar flare and that's a visible event that is seen about eight minutes later from earth or it's seen even sooner from spacecraft. It takes about eight minutes for the sun's light and radiation to travel to earth. Then there's an associated event that is sometimes cast out from the sun called a coronal mass ejection. Yesterday's solar flare also had one of these coronal mass ejections. The initial event hit earth yesterday very rapidly after eight minutes or so. Today, earlier this morning the more devastating event or the more important event was this coronal mass ejection, a giant blob of gas, a big cloud that just expands outward and travels through space.
MARGARET WARNER: And I gather it's just huge, what, 13 times the size of Earth?
ROBERT ROY BRITT: The sun spot itself is many times the size of Earth. It's as big as Jupiter. The expanding gas cloud is much larger than Earth, yes.
MARGARET WARNER: All right. So it approaches Earth and hits the Earth's what, atmosphere and magnetic field? What then could happen? What did scientists fear was going to happen?
ROBERT ROY BRITT: Yeah. You think of Earth as a giant magnet, and coming out from the poles are these magnetic field lines that come out and go all the way around the earth and they actually go out beyond the atmosphere. Those generally protect Earth from these charged particles that race out constantly from the Sun. But when you get a big storm like this one, it can overwhelm the magnetic field. And scientists feared that the two magnetic fields, the one of earth and the one that's associated with the storm might be aligned in opposite directions. If that had happened, things might have been worse. As it turns out the magnetic fields were aligned in the same direction and the storm -- it was powerful and we felt it but it wasn't as bad as it could have been.
MARGARET WARNER: Well, I noticed the headline on your story this morning on Space.com was space storm hits, Earth survives. I don't know if that was tongue in cheek but tell us, what really was the impact. Was most of the impact precautionary steps that were taken or did it actually seriously disrupt some communications?
ROBERT ROY BRITT: One Japanese satellite has been temporarily disabled and it may have suffered some permanent damage, we don't know yet. Some power grids were reported to have shifted how they control their power. They try to reduce the amount of flow and not do any major power exchanges with other companies. The interesting thing is that because these storms can be forecasted now with some accuracy by the folks who run the Soho spacecraft, and the equivalent of the National Weather Service for space, run out of Boulder, Colorado, the power companies and the satellite operators can take some measures to keep the storm from damaging things the way it might have.
MARGARET WARNER: So, in other words, that's why the effect wasn't half as bad as in 1989 when Quebec Province went dark for nine hours and there were all kinds of disruptions here?
ROBERT ROY BRITT: That's right. This was a similarly powerful storm but people have learned, the engineers have learned a lot since then. We didn't have a solar forecasting department then -- solar weather forecasting. We do now.
MARGARET WARNER: This afternoon the federal scientist as the NOAA, the National Oceanic Atmospheric Administration, said this storm, first of all, is still going to kind of be around on Earth, I'm probably not using the right word there, but anyway, with us up for to 24 hours, and there could be further eruptions in the next week. Do they think the worst is the over or could the worst get be to come?
ROBERT ROY BRITT: Yeah. I talked with Joe Conchus there at NOAA's lead forecasting office for space weather this morning. He told me that this storm will probably linger about 24 hours, so that puts us into tomorrow morning, still. We could have some bright colorful lights, the aurora tonight that could extend this evening into the United States and into Europe. And I just spoke with Paul Brecky, a scientist with the Soho spacecraft, just before I came in here. There was another major eruption this evening from the sun and the effects of that storm we could feel tomorrow or the next day.
MARGARET WARNER: Rob Britt, thanks so much
ROBERT ROY BRITT: Thank you.