the salt makers

More solar evidence:

http://space.newscientist.com/article.ns?id=dn11432&feedId=online-news_rss20

The restless bubbling and frothing of the Sun's chaotic surface is astonishing astronomers who have been treated to detailed new images from a Japanese space telescope called Hinode.

The observatory will have as dramatic an impact on our understanding of the Sun as the Hubble Space Telescope has had on our view of the universe beyond, scientists told a NASA press conference in Washington, DC, US, on Wednesday.

"Everything we thought we knew about X-ray images of the Sun is now out of date," says Leon Golub from the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, US. "We've seen many new and unexpected things. For that reason alone, the mission is already a success."

Hinode (Japanese for "sunrise") was launched in September 2006 to study the solar magnetic field and how magnetic energy is released as the field rises into the Sun's outer atmosphere. The mission was formerly known as Solar-B.

Seething and swaying

The spacecraft carries an optical solar telescope (SOT), an X-ray telescope (XRT) and an ultraviolet spectrometer. It orbits the Earth in a permanent twilight zone between night and day, which gives it a continuous view of the Sun.

Hinode has sent back startling images of the Sun's outer limb. Where astronomers expected to see a calm region called the chromosphere, they saw a seething mass of swaying spikes (see image below right, and watch a video of the spikes taken by Hinode).

"These structures are 8000 kilometres long and some extend twice that high," says SOT science team member Alan Title from Lockheed Martin Advance Technology Center in Palo Alto, California, US. "Their speed is such that if you sat on the end of one, which I don't recommend, you could travel from Washington, DC, to San Francisco in about four minutes. These things are really moving."

Crashing loops

Another surprise sighting is that of giant magnetic field loops crashing down onto the Sun's surface as if they were collapsing from exhaustion, a finding that Golub describes as "impossible". Previously, scientists thought they should emerge from the Sun and continue blowing out into space.

"Almost every day, we look at the data and we say – what the heck was that?" says Golub, a member of the XRT science team.

Astronomers do not yet know what to make of the surprises, but they hope Hinode will help solve many big puzzles. One is that the temperature of the Sun's tenuous outermost atmosphere, or corona, is far hotter than the layers underneath, which are nearer its energy-generating core.

Scientists believe that tangled magnetic fields must somehow dump energy in the corona. "Theorists suggested that twisted, tangled magnetic fields might exist," says Golub. "With the XRT, we can see them clearly for the first time."

Astronomers hope Hinode's clear view of the Sun will also help them identify the magnetic field configurations that lead to the most explosive energy releases of all. That would enable better forecasts of stormy "space weather", when solar eruptions can interfere with satellite communications and disrupt electricity supply networks on the ground.