That’s a Big Tsunami
You think we have tsunami problems? Imagine a wave of superheated plasma and magnetic energy over 7 1/2 times taller than Earth* rushing toward you at 560,000 miles per hour.
That’s what the twin STEREO satellites spotted when it got the first very good image of something called a a magnetohydrodynamical wave (also called a solar tsunami) back in February. Scientists have seen these waves before, but they’ve never been entirely sure if they weren’t seeing some sort of shadow or image artifact. Thanks to the better imaging from STEREO, they now know solar tsunamis are real and spectacular.
Okay, so where’s the practical angle here? Well, solar tsunamis are caused by Coronal Mass Ejections — big honking eruptions on the sun that blast billions of tons of gas toward us and the rest of the planets. CMEs can reach speeds of up to 1.6 million MPH, which means that we’ll get a touch over 58 hours of warning* before we get hit by one of the faster ones.
CMEs play hell with electrical systems when they strike the Earth’s magnetosphere. They can potentially disable satellites, damage sensitive electronics, and cause widespread power outages. Obviously, we’d like to know when one’s heading our way as soon as possible (as opposed to having to relyalmost solely on a single 11 year-old satellite)and that’s where STEREO helps us. Thanks to that mission, we can get a better look at an Earthbound CME almost as soon as it erupts and we’ll know more about it (size and speed, especially) than we’ve known in the past.
Also, we get amazingly cool videos like this.
*As always, feel free to recheck my math here (or, for that matter, any math you see on The Shack. I try to get it right, but math is far from my strongest subject. Unlike the Climate Research Unit, I don’t mind if you check my work and correct my mistakes.
Related posts:
- The Most Impressive Tsunami Video I've Ever Seen (Or, How the Sea Ate a Town in 6 Minutes)
- It's A Shame that John Bad Mutha Shut Yo Mouth Didn't Discover This Comet
- We Love the Moon!
- So Long and Thanks for All the Science!
Category: Hey, Mr. Science Guy!
About the Author (Author Profile)
Subscribe
If you enjoyed this article, subscribe to receive more just like it.
This is an impressively well linked post.
I'll just mention that STEREO isn't actually intended as an early warning system (or it would have required a longer mission life); the goal is to find what sort of activity happens before a CME; that's the first step to actually forecasting these events, possibly even just from terrestrial telescopes.
Why thank you! I wanted to make sure I had background for some of the big terms I had used (and since I needed to look up a couple of those links anyhow, for my own purposes, I figured I may as well share them).
I know it's not supposed to be an EWS, but it certainly could be. From what I've seen, it would give us enough data to serve that purpose, almost incidentally. The one satellite we're using as a warning now has more than doubled its mission life. On that track record, we could probably use STEREO for that as well. Though I would certainly like to see terrestrial telescopes purposed for that as well.
And searching for asteroids heading our way, too.
True enough–but STEREO's mission life was only two years, and it's already at 37 months. The spacecraft have excellent chances of lasting longer…the design life is actually five years…but they're still moving away from Earth, and that means the coverage is gradually degrading, even if the telescopes continue working perfectly. When they get to the other side of the Sun, communications will be lost, regardless; we can't be sure of recontacting them, months later, when they reappear.
So, yes, we can use them for early warning in the near future, but that time is more sharply limited than some existing spacecraft. Hopefully there will be follow-on missions, but that depends on the politicians.
Hrm….that's distressing. I didn't know that the satellites were still moving. I was under the (mistaken) impression that they were in a stable position.