Sunspot Activity Highest in 1,000 Years, Scientists Say

Last Updated: Monday, November 3, 2003

CBC News Online staff

TORONTO
The sun has been acting unusually lately, scientists say, with more sunspots recorded since the 1940s than in the previous millennium.

Scientists in Europe have reconstructed sunspot activity for the last 1,150 years and found that lately the sun has been showing a lot more activity.

Sunspots, the relatively dark patches on the surface of the sun, are an indication of intense magnetic activity on the inside.

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Direct observations of sunspots go back to the early 17th century, corresponding to the invention of the telescope.

To get data on sunspots from before observations were possible, Ilya Usoskin, a geophysicist who worked with colleagues at the University of Oulu in Finland and the Max Planck Institute in Germany, examined ice core samples from Greenland and Antarctica.

The ice cores provide a record of beryllium-10, a radioactive isotope, in Earth's atmosphere. The isotope is produced when high-energy particles from space hit the atmosphere.

When the sun is showing more sunspot activity, though, its magnetic field protects the Earth from the particles and levels of beryllium-10 are lower.

It was already known that levels of beryllium-10 in the atmosphere are much lower now then they have been in a long time, but this is the first time it's been used to calculate the magnetic activity of the sun.

The research appears in the journal Physical Review Letters.
(Source: CBC News Online)
2003 © Canadian Broadcasting Corporation.

Dan