Posted by “Events are the ephemera of history; they pass across its stage like fireflies, hardly glimpsed before they settle back into darkness and as often as not into oblivion. Every event, however brief, has to be sure a contribution to make, lights up some dark corner or even some wide vista of history… illumined by the intermittent flare of the event.” -Fernand Braudel
The spectacular event of the day, however, isn’t something that started on Earth. Rather, 93 million miles away, it was our Sun, early yesterday morning (about 38 hours ago as I write this), that had a brief… shall we say… outburst. NASA’s Solar Dynamics Observatory got the best view of this event as it happened, looking in extreme ultraviolet (13.1 nanometer) light, and collapsed the one-hour flare into a meager seven seconds.
What you just witnessed was a relatively powerful Solar Flare, at class M8.7. (M is the second highest class, behind only X.) While it’s nothing compared to the biggest ones we’ve recently seen, Solar Flares can occasionally spell trouble for us here on Earth.
Image credit: NASA / SOHO.
Why’s that? Because Solar Flares are often accompanied by Coronal Mass Ejections (CMEs), as shown above in this 2002 SOHO image.
So what’s so special about yesterday’s Solar Flare?
Image credit: NASA/SDO and the AIA consortium. Edited by J. Major, retrieved from flickr user Lights In The Dark.
This Solar Flare produced a CME directed towards Earth, and since it’s moving at around a whopping 1,000 miles per second, that means it’s arriving… right around… NOW!
That’s right, the largest solar storm since 2005 is going to hit Earth today/tonight, particularly right at the edge of the Northern Hemisphere! Here are a bunch of time-lapse views of the flare from the Sun from a number of different satellites, courtesy of space.com.
A coronal mass ejection is when this heated plasma stream of electrons, protons, and heavy ions gets launched out of the Sun in a random direction in space. This charged radiation can totally do some damage to electronics; that’s what the speckling you saw was! (There’s a nice explanation and video by Phil, here.) What about you, you may ask?
You are fine. Know why? Because of this.
Image credit: NASA/Goddard Space Flight Center, retrieved from SWRI.
The Earth’s magnetosphere protects us from this radiation! The magnetosphere bends the charged particles that would strike most regions of the Earth away from the equatorial regions, and funnels them only around the polar areas. As the particles come down towards Earth, they interact with the atmosphere, which does an excellent job of stopping them before they ever make it to the surface. In fact, this particular CME will mostly miss the Earth (remember, Earth is tiny on the scale of the Solar System), flying over the North Pole. Still, our magnetic field will bend some of these charged particles into the Earth’s atmosphere! Know what that produces?
Image credit: Bjørn Jørgensen; today's Astronomy Picture of the Day!
The Aurora Borealis, or the Northern Lights! (If the flare had been below the South Pole, we’d have gotten the Southern Lights, or Aurora Australis, instead.) Anyone with clear skies in the Northern Hemisphere should go and look for them tonight; we don’t know how far South they’ll be visible, but even places that very rarely get aurorae might be in luck tonight!
You know who’s going to get the best view?
Astronauts on board the International Space Station! You might be worried that the astronauts on board would not be shielded by the magnetosphere, and so would be in grave danger from a coronal mass ejection like this. After all, at 240 miles above the surface, there’s no atmosphere to protect them by absorbing all the protons, ions and electrons!
So what does that mean; do the astronauts absorb this radiation directly?
Image credit: NASA, retrieved from Paul Floyd's article.
No, the ISS has a hull designed to shield them from this type of radiation. As this Universe Today article details, everyone and everything on board the ISS will be totally safe. In fact, any well-designed satellite will have shielding against the radiation from CMEs; the only pitfall is that most of them — including GPS satellites — were built cheaply, and don’t have this type of shielding. That’s the only type of danger from a flare / CME like this.
Yes, it’s true that tremendous solar storms can be problematic, particularly for large power lines, plants, and grids, but this is not that storm. But the coming aurorae?
As Teri Hatcher would say, “they’re real, and they’re spectacular.” Get out there tonight if you’ve got clear skies and have a look. Good luck!
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