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SYFY WIRE Bad Astronomy

Millions of Tons of Gas Hangs Over Our Star

By Phil Plait

I have got to get a solar telescope. Why? Because this:

That is a gorgeous shot of the Sun (which you really want to click to embiggen) taken by Spanish astronomer Paco Bellido on July 23. He was using a Coronado Solarmax telescope that was equipped with a special filter that shows warm hydrogen roiling on and above the surface of the Sun.

The image is inverted, so that dark material appears bright and vice versa. Long curls of filaments hang across the Sunâs face; megatons of hydrogen plasma suspended by our starâs powerful magnetic field. They really look three-dimensional, donât they? Bellido made a red/green anaglyph version if you have the glasses for it, and that makes those filaments really pop out.

Sometimes filaments collapse back onto the Sunâs surface, and sometimes they erupt away. Alan Friedman, whose work has been on this blog many, many times, was observing the Sun on July 26 and caught one suspended without visible support above the Sunâs limb:

In fact that hydrogen is trapped in the Sunâs magnetic field, so it was being supported (and, Iâll add, when a filament is seen against the backdrop of space itâs called a prominence). Friedmanâs image is also invertedâhe created a positive one for purists, too, if you'd like to see it. In the larger version of his picture you can see tremendous detail, but note that the Sun is about 1.4 million kilometers (860,000 miles) across, so something that looks small still dwarfs our entire planet! That filament you see wrapping around the Sun at the upper left is probably 300,000 km in lengthâalmost enough to stretch from the Earth to the Moon.

Iâll note that we should now be approaching the peak of the solar magnetic cycle, when sunspots should be numerous and activity on the rise. However, the Sun hasnât been holding up its end of the bargain; itâs still way below what weâd expect it to be doing. This whole cycle has been weird literally since it started, and Iâm still not sure what the Sunâs going to do. Will it come roaring back, or will it continue to fizzle? Only time will tell.

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