Solar Science

A blog of solar physics

Posts Tagged ‘sunspots

It comes from the Far Side..?

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After being starved of any significant solar activity for so long, any detection of a sunspot very nearly becomes headline news. Therefore when a significant spot is detected on the solar farside, people start writing furiously.

So what to do? The first detection of a potential (and substantial) sunspot in more than a month came from GONG

But will it survive to the nearside?

There’s something that might be a spot on the far eastern limb of the latest STEREO image

But GONG now shows nothing at all

GONG data as of 16th September 2009

GONG data as of 16th September 2009

So what to believe? The next few days should show whether we’re looking at a spot or a plage. I confess that the sensitivity of the seismic results interpreted by GONG are often less accurate as to whether we are seeing a solar disturbance (like a coronal hole or a prominence) or a real sunspot.

I suspect that this is continuation of a pattern we have been seeing for many months, a single sunspot or very small group with SC24 polarity passes in front of us, but nothing else happens and the Sun’s activity quickly falls back to very low levels.

Because of this phenomenon, the most likely response from the solar science community is likely to be muted, after so many false dawns.

Solarcycle24.com has produced a graph showing the remarkable difference between the spotless days between solar cycles 22 and 23 and between 23 and 24.

There’s no end in sight for this minimum.

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Written by John A

September 16, 2009 at 9:15 pm

Posted in Solar Cycle 24

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Solar Cycle 24 finally arrives

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Not a speck. Not a low latitude could-be-a-SC23 spot.

The real deal.

Sun on 13-10-2008 showing SC24 spot

Sun on 13-10-2008 showing SC24 spot

The polarity is definitely reversed from the previous cycle. Its a high latitude spot. The companion spot is reverse polarity to the main spot.

Looks good to me.

The STEREO image (allows us to look around the limb of the Sun and see what’s coming) suggest an even larger area of activity at about the same latitude.

Stereo Image 12-10-2008

Stereo Image 12-10-2008

Now we wait to see if the SC24 persists.

The magnetogram shows the SC24 polarity:

Magnetogram from 13-10-2008 showing SC24 polarity

Magnetogram from 13-10-2008 showing SC24 polarity

The solar magnetic field for September has just been published (as graphed by Anthony Watts) and shows the magnetic field to be at a historically low level, as NASA had already noted.

solar_ap_index_10062008.png

This may just prove to be the bottom of the Solar Cycle (yes, I’m sticking my neck out). Now we wait to see what happens next, because I’m not convinced that anyone really has a clue.

Written by John A

October 11, 2008 at 11:16 pm

Solar Cycle 24: Do we count Tiny Tims?

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Another week of excitement as the second solar cycle 24 spot appeared…and then disappeared just as rapidly.

I can’t help feeling that with an unprecedented amount of high technology monitoring the Sun with ever higher resolution, the criteria by which a sunspot is defined has become radically weakened to such an extent that it all becomes meaningless.

On Climate Audit commenters noted that the criteria for naming hurricanes had become so weakened that practically any frontal wave in the Eastern Atlantic that persisted for more than a few hours got a name (the so-called “Tiny Tims” of the hurricane season).

So it appears to be with sunspots and Solar Cycle 24. Here is that second solar cycle 24 sunspot numbered for all to see:

mdi_sunspotsgif.jpg

Now in order to ascertain that there really is a spot there, I had to first make sure my laptop screen was really clean because it could have been hidden behind a rogue speck of dust and I could have missed it.

Can you spot it? If so, you’re better than I.

Here’s three views looking at the same spot. It may be there in the magnetogram showing the class signs of magnetic polarity reversal and there may be an associated phage (often the precursor of a sunspot) but is there a sunspot?

spotthesc24spot.jpg

Meanwhile a few days later, yet another SC23 spot comes into view.

I can’t help but feel that this is all a little desperate. SC24 continues to surprise with its general unwillingness to make an unambiguous appearance.

Written by John A

April 19, 2008 at 4:20 am

Posted in Solar Cycle 24

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