The Sun in Stereo(26/07/2007)
Storms on the sun have crashed satellites, computer systems and power grids here on Earth. The reason is that the sun occasionally throws out giant belches of plasma, known as coronal mass ejections, which travel through the solar system swamping the planets and playing havoc with the Earth’s electronics. We desperately need a good way of predicting when a coronal mass ejection will hit. To do the job NASA has launched a pair of almost identical spacecraft. The on-board cameras on these Stereo craft will not only help predict bad space weather. They have already provided the first ever three dimensional pictures of the sun. Have you 3D glasses ready for this one!
Reporter/Producer: Dr. Graham Phillips
Researcher: Anja Taylor
Dr Graham Phillips: These are parts of the old telegraph system we used for long distance communication a century or two ago. Now here’s an interesting story. In 1859 there was a massive storm on the sun and are parts of the telegraph system were shorted out. The result was spot fires around the world. There’s nothing stopping another massive storm today, and imagine the damage it could do now given how dependent out lives have become on electronics.
Narration: That super-storm was a bad one, but lesser storms have already crashed computer systems, caused power surges in the electricity grid, and disrupted communications and satellites. We desperately need a reliable way of predicting when bad space weather will hit.
Dr Charlie Lineweaver: We’re in the situation with space weather as we were in Earth weather in the 1950s. In the 1950s, to find a hurricane, you’d have to say “here comes one Joe, let’s get into the house and cover up”. But now we have satellites that tell us when these hurricanes are coming – days and weeks in advance sometimes.
Narration: To get advanced warning of a dangerous sun storm, NASA has launched an unusual probe. Two nearly identical spacecraft– the stereo craft. …they should give us warning. And … provide the first ever 3D pictures of the sun.
But first, what is a solar storm?
Dr Charlie Lineweaver: The surface of the sun is a very frothy…filaments and flares bubbling
Now if you’ve ever seen a pot of spaghetti boiling or water boiling. It goes blub blub blub and its boiling and frothing all the time.
And you get spaghetti splattered all over the walls. That’s what’s going on. The sun is splattering itself all over the solar system and we call that the solar wind, solar flares. And occasionally a big blob comes off and that is a coronal mass ejection.
Narration: A coronal mass ejection – a CME - is a huge belch of plasma from the sun’s surface. It’s made up of mainly protons and electrons, and can travel right through the solar system, swamping planets… and messing with the Earth’s electronics.
Dr Charlie Lineweaver: Because what happens when they come is that they have their own magnetic field and they make the magnetic field of the Earth change with time. That puts a current, that creates a voltage. And if you have a very very long wire like the power grids have then you’re creating a high voltage. So you’re having high voltage and low voltages as the thing swings over the wires
Narration: Now astronomers can already measure some of the sun’s CMEs without the stereo spacecraft. They look at the partially blocked sun through a chronograph and can see the ejections streaming off.
Dr Charlie Lineweaver: But those are the ones going sideways! They’re not going to hurt the Earth; they’re not going to hurt us. The ones that are going to hurt us are coming towards us. And they’re the ones we know least about…you know how fast they’re coming how big are they, what their structure is. When they will hit.
Narration: That’s where the stereo spacecraft come in. They orbit the sun separately…so their onboard cameras take the same photo but from different angles. The images are combined creating a 3D picture of the sun, which will allow the speed of those head-on CMEs to be calculated.
Dr Charlie Lineweaver: If we could see them launching from the sun we have a few days to work out how fast it’s coming. To work out what hour or what minute it will arrive in the upper atmosphere.
Narration: With advanced this warning we can temporarily shut down communications satellites and protect the power grid.
And as for Stereo’s pictures…they look stunning. For the full effect you need 3D glasses. To find out how to make some and for links to these movies go to our web site.
Hopefully, an early warning system based on the stereo craft will be in place before another 1859 super-storm strikes.
- Reporter: Graham Phillips
- Producer: Graham Phillips
- Researcher: Anja Taylor
- Camera: Ian Warburton
- Sound: Grant Roberts
- Editor: Ben Eriksen
Dr Charlie Lineweaver
Planetary Science Institute
Research School of Astronomy and Astrophysics