First 3D pics shed light on solar storms

25 April 2007

Space scientists have revealed the first ever 3D images of our Sun. Taken aboard NASA's twin STEREO spacecraft, the new pictures aren't just pretty. Researchers hope they'll help to track down solar storms which can knock out satellite communications kit. Antenna finds out more...

This is one of the first pictures taken on the STEREO mission.

Image: NASA

Our Sun is more than just a source of scorching heat and bright light. Enormous explosions on its surface frequently throw more than a billion tonnes of electrically charged particles hurtling out into space.
When these eruptions combine with solar winds the result is a powerful 'solar storm', which can cause major damage to satellite communications equipment. Now NASA's STEREO mission has beamed back images that could help experts predict these outbursts and limit the damage they cause.

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This video shows what space scientists think these giant eruptions, called coronal mass ejections, look like.

Video: NASA

Chris Davis, a UK space scientist involved in the project, explains: 'At the moment we don't know when and how solar storms happen. It's only by getting a 3D view of the Sun that we'll be able to understand the exact conditions that set them off. This is where the STEREO mission comes in.'

Space expert Chris Davis from the Rutherford Appleton Laboratory is helping to decipher the data from the STEREO mission.

Image: Rutherford Appleton Laboratory

The Solar Terrestrial Relations Observatory mission (STEREO) launched into action on 26 October 2006. But instead of just one craft, STEREO is made up of two nearly identical spacecraft, each the size of a large golf cart. It's this key feature that allows STEREO to build up 3D pictures.

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STEREO's twin spacecraft lifted off together aboard a Delta II rocket from Cape Canaveral Air Force Station, Florida, and then separated in space.

Video: NASA

How does it work?
Both STEREO's spacecraft orbit the Sun. One moves ahead of the Earth and the other lags behind. Just as the different views from our eyes allows us to see depth, by combining pictures of the Sun at these two angles STEREO can get images in 3D.

The arrangement of the two spacecraft also means they can take measurements of local particles and magnetic fields around them.

Image: NASA

So far so good...
'The mission is going extremely well so far and I'm really excited about seeing these pictures,' says Chris Davis. 'They're showing us lots of different things as well as these solar outbursts - this month we saw a comet go past the Sun and we've seen images of Venus too.'

This is one of the latest 3D pictures from the STEREO mission, but you'll need 3D glasses to see the full effect.

Image: NASA

Chris Eyles, another space expert on the project agrees. 'This is the first time we've ever had 3D pictures of the Sun so they're very exciting. Before now we only had pictures that were taken from cameras on a single spacecraft.'
'But these pictures are only the first step in STEREO's two-year mission. At the moment the angle between these two spacecraft is quite small, so they're giving us quite similar pictures of the Sun. As the two spacecraft separate over time, we will actually be able to take pictures of solar eruptions as they travel towards the Earth,' he says.

Chris Eyles from the University of Birmingham was part of the UK team that helped build STEREO.

Image: Chris Eyles

So why are solar storms such a problem?
Chris Davis explains: 'When directed at Earth, solar storms can cause major damage to satellites in the Earth's orbit and disrupt our communications systems. In the past they've also disrupted power grids - in 1989 a solar storm took out the power in Quebec in the middle of winter.'
'Plus they could also seriously injure astronauts that happened to be outside of the Earth's magnetic field at the time. Being able to predict when and what direction these outbursts will happen in is a vital part of exploring the Solar System.'

Image: NASA

'By understanding solar storms better we'll be able to forecast when a major outburst is going to happen and take steps to protect against the problems they cause,' says Chris Eyles.
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