terça-feira, 7 de outubro de 2008

Hurricane-sized whirlpools spotted on the Sun

October 2008
By Devin Powell



Hurricane-sized whirlpools have been spotted spiralling on the surface of the Sun, confirming theories about how material convects in the Sun's roiling outer layers.

The scalding soup of charged particles, or plasma, in the outer 30% of the Sun is thought to rise and fall in churning cells, like macaroni bobbing in a pot of boiling water.

After the hot material rises, it releases energy and falls downwards. Because it already has some sideways motion, this cooler plasma should spiral into the Sun as it falls – like water running down a bathtub drain.

But observations over the past two decades have failed to spot these small whirlpools, which require a very high resolution to detect.

So Jose Bonet of the Instituto de Astrofísica de Canarias in Spain and colleagues went looking for the patterns using the Swedish 1-m Solar Telescope, which can observe details as small as 90 kilometres across.

The team tracked bright spots produced by moving plasma. The spots showed a swirling pattern about the size of a hurricane on Earth.

After further observation, the team found 138 of these whirlpools, each of which survived for only 5 minutes before disappearing.



Source: http://space.newscientist.com

Sem comentários: