Mapping the sun

AS EUROPE swelters under a heatwave, it seems like the perfect time for scientists to turn their attention to the Sun.

Our parent star, its violent mood swings and the dangers they pose to the Earth will be the focus of the Stereo mission, a $500 million probe due to launch in August.
Stereo is made up of a pair of satellites — each more than half a tonne in mass and the size of large deep freezers — which will help to build up the first ever three dimensional model of the Sun. The information it gathers will help keep everything from global positioning systems to mobile phones working properly in the future.
“While the Sun may appear to be one of the most familiar objects in the sky, it is constantly changing,” said John Zarnecki of the Open University, Britain. “We need to understand its mood swings more fully in order to predict and, more importantly, protect the potentially devastating effects — particularly of the coronal mass ejections (CME).”
The CMEs are events where more than 1,000 million tonnes of charged particles are hurled into space at an average speed of 1.6 million kph. If the particles reach Earth, they can damage orbiting satellites and disrupt electronics and power grids at the surface.
“In 1859, a giant solar storm erupted, hurling hot plasma towards the Earth. Fortunately that happened before the space age, so the effects were fairly tame,” said Prof Zarnecki. “Had that storm happened today, communications and navigation satellites would have taken the full impacts. Forecasts suggest that a major outburst such as that would have had a similar economic impact to category 5 hurricane.”
With current satellites such as the Solar and Heliospheric Observatory (Soho), launched in 1995 to study the Sun, scientists get an hour’s notice of a stream of plasma due to a CME heading for Earth. Stereo will increase that warning to around two and a half days, which could give enough time to prepare.
At the heart of each Stereo satellite is the British-built heliospheric imager. With a broad field of view, the imager will study how the CMEs spread from the Sun, particularly those heading for Earth.
Once launched into space from Florida by a Delta II rocket, Stereo’s two consistent probes will eventually separate and move apart at a few hundred thousand kilometres a year.
If all goes well, scientists hope to get the first measurements from the mission will emerge by November. The mission has a nominal lifetime of two and a half years but there is no reason it could not last much longer. 

sun sessions
GW’s top 10 tracks featuring the sun
1) Here Comes the Sun — Beatles
2) Black Hole Sun — Soungarden
3) Sunshine Superman — Donovan
4) Don’t let the sun go down on me — Elton John
5) Steal My Sunshine  — LEN
6) Sun King — Beatles
7) Sunshine on my shoulder —  John Denver
8) You are the sunshine of my life — Stevie Wonder
9) Invisible Sun — The Police
10) The Sun Ain’t Gonna Shine Anymore — Neil Diamond