Tornadoes discovered on the sun

Artists impression of the hot solar atmosphere

Astronomers have discovered that our sun has huge gyrating storms far larger and faster than tornadoes on the Earth. Our science correspondent David Whitehouse reports:

"We see hot gas in the tornadoes spiralling away from the sun and gathering speed," says David Pike of the UK's Rutherford Appleton Laboratory.

Helen Mason of Cambridge University, co-discoverer of the solar tornadoes, adds: "These spectacular events in the sun's atmosphere must have widespread effects."

The Soho satellite monitors the Sun

The tornadoes were discovered using the Soho solar observation satellite, which was launched in December 1995.

Soho is in a special orbit on the sunward side of the Earth thereby able to maintain constant monitoring of the sun.

So far, scientists have detected a dozen tornadoes. They occur most frequently near the north and south poles of the sun and are almost as wide as the Earth.

The superheated gas in the tornadoes travels at speeds of up to 150km a second. Tornadoes on Earth only reach up to 500km an hour.

Solar tornado wider than Africa

The newly-found storms on the sun may contribute to the solar wind, a stream of particles blown from the sun. During periods of intense solar activity the solar wind can cause power failures in Canada and Sweden as well as damage to satellites.

During its two years of scientific observations of the sun, Soho has improved our knowledge of our nearest star.

Violence on the Sun's surface

It has found sub-surface 'jet streams' of superhot gas, so-called rivers inside the sun. They may play a role in the sun's 11-year cycle of sunspot activity.

Soho has also discovered the reason why the sun's outer atmosphere, the corona, is 300-times hotter than the sun's surface. It appears that energy is transferred to the Corona from underneath the sun's surface by a 'magnetic carpet'.