News

A Sunspot Flares Up - Public talk


25 January 2010

In late 2009 a small region of sunspots broke an unusual dry spell with little sunspot activity. This activity interrupted a two-year quiet period for the Sun, with few or no sunspots. The last time the Sun was this quiet was in 1913.


Solar and Heliospheric Observatory, ESA/NASA.
Solar and Heliospheric Observatory, ESA/NASA.

"What made this even more unusual", says Associate Professor Mike Wheatland, an astrophysicist from the School of Physics at The University of Sydney, "was the fact that this little region was very solar flare intensive. And this region did not follow an observed rule."


Wheatland says there are usually many small flares and a few big ones following a simple law, but this region didn't abide by the law. "It was punching well above its weight in terms of production. It produced too many small flares and too few large flares." A paper on this result is scheduled for a February issue of the Astrophysical Journal.


Wheatland says that while the centre of the Sun is the hot spot at 15 million degrees, solar flares can generate temperatures of tens of millions of degrees. Solar flares also produce energetic particles in our local space environment, which are a cause of concern for astronauts and for communication satellites.


"It was recently estimated that if we got a very large solar flare such as the one that occurred way back in 1859 (Carrington's Flare), the damage to satellites could amount to $US70 billion," says Wheatland, who has been working on flare prediction methods with NASA. "Unfortunately the prediction methods are statistical, and not entirely reliable - it is somewhat like reading tea leaves," he grins.


Wheatland's research into sunspots, which are regions on the sun with strong magnetic fields that power solar flares, will be highlighted at his free public talk, A Sunspot's Tale, to be given at the Sydney Observatory on Monday 1 February 2010 at 6.30pm.


Contact: Sydney Observatory

Phone: 02 9921 3485