Backward Sunspot

[Kain]

Thought this may interest the solar watchers among us

http://science.nasa.gov/headlines/y2006/15aug_backwards.htm

Wern't sure whether to put it here or in the Solar forums, so apologies if it's wrong!

Kain

[daz]

Here's good

Astroman - how do you tell if it's backwards - is it the orientation of the 'light' and 'dark' elements??

[Astroman]

Cool! 8)

The link actually explains it. The black and white image from the magnetogram shows the polarity of active regions on the Sun. The Sun rotates from left to right. Magnetic polarity of active regions are black for south and white for north. Since the Sun rotates left to right, we see all the magnetic poles rotate toward the south poles, except this one tiny spot on the limb which has the north pole leading. We define the solar maximum having been reached when the overall polarity of the Sun reverses from top to bottom. South magnetic polarity is now on "top" of the Sun as we see it, and north at the "bottom". This is just the reverse of what it was before solar max back in 2000-1. We are now starting to see it in individual spots, so it means the new cycle is beginning, but don't expect activity to pick up very quickly, as I've said before. It's just the beginning, and it's a tiny spot.

Nice catch, Kain!

[Kaptain Klevtsov]

So how does a magnetogram work I wonder? Is magnetism detectable at such long range?

Captain Chaos

[Astroman]

You would ask me that. :shock:

It's a spin-off of spectroscopy. When you observe the Sun as a spectrum, you see lots of dark absorption lines across the bright continuum, (read, "rainbow"). To see specific details, you tune in to one particular dark absorption line. Normally, the line is well defined, but in the presence of very high magnetic fields, the line can be widened, distorted or even split in two. This is called the Zeeman effect. The specific line, extent of the distortion and direction of distortion tells us a lot about the intensity, temperature and polarity of the magnetic field causing the effect. These are then mapped as an image like you saw in the previous posting.

I hope that helps.

[Kaptain Klevtsov]

It does indeed AM. I was convinced that the magnetism could only be measured directly by having the sensor locally, but this inferential method sounds marvellous. Sounds like a kind of red-shift thing but measuring the stuff affected by the magnetism, ace idea.

Thanks very much,

Captain chaos

[Astroman]

No problem, CC.

It's always a challenge to explain complex concepts such as this. Glad to see your eyes haven't glazed over, as I've seen so many times in others.

[Kain]

Sunspot 905 is also backward according to Space Weather.

Kain

[Astroman]

Sunspot 905 is also backward according to Space Weather.

Kain

Looks backwards to SOHO, too.

http://sohowww.nascom.nasa.gov/data/realtime/mdi_mag