Solar Science

A blog of solar physics

Archive for October 2008

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

The Sun is in a deep minimum

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Yesterday I pulled this magnetogram picture from the SOHO website

20081006_0141_mdimag_512.jpg

Ignoring the phage in the Southern Hemisphere (which is SC23 polarized, natch) there is no magnetic activity at all to speak of.

Throw in the result announced by NASA in the last few days:

“The sun’s million mile-per-hour solar wind inflates a protective bubble, or heliosphere, around the solar system. It influences how things work here on Earth and even out at the boundary of our solar system where it meets the galaxy,” said Dave McComas, Ulysses’ solar wind instrument principal investigator and senior executive director at the Southwest Research Institute in San Antonio, Texas. “Ulysses data indicate the solar wind’s global pressure is the lowest we have seen since the beginning of the space age.”

and

In 2007, Ulysses made its third rapid scan of the solar wind and magnetic field from the sun’s south to north pole. When the results were compared with observations from the previous solar cycle, the strength of the solar wind pressure and the magnetic field embedded in the solar wind were found to have decreased by 20 percent. The field strength near the spacecraft has decreased by 36 percent.

“The sun cycles between periods of great activity and lesser activity,” Smith said. “Right now, we are in a period of minimal activity that has stretched on longer than anyone anticipated.”

Its clear that the Sun has entered a phase that we might never have seen before with anything like modern instrumentation.

The spots on the Sun have become so evanescent and small that we now have the ludicrous arguments over whether a darkened spot that lasts a few hours is counted as a spot or a speck. Anthony Watts refers to this as “Speckwatch” and furthermore even these specks have been SC23 not SC24 polarized.

What is clear is that these spots or specks are way below the range at which our scientific ancestors from the 18th and 19th Centuries could ever have detected.

Written by John A

October 6, 2008 at 1:54 pm

Posted in News and Views

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Predicting the Future ain’t what it used to be

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A quick update on David Hathaway’s predictions for Solar Cycle 24.

Dr Hathaway has changed his prediction once again WITHOUT changing the page that it occurs on (other than the date it was updated), nor with any explanation as to why his previous predictions have been so wrong. It would be nice if he would treat us all to an explanation for modifying his prediction without modifying his methodology.

Here is an animation done by Michael Romayne on how Hathaway’s prediction has changed over time.

Hathaway predictions to OCtober 2008

Its clear that something so flexible as Hathaway’s predictions cannot have a theory behind them – this is just making ad hoc adjustments. Note also that between March 2007 and March 2008, the expected size of SC24 was reduced – why?

h/t to Anthony Watts 

Written by John A

October 6, 2008 at 12:54 pm

Posted in Solar Cycle 24

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Like the Sun, I’ve been in low power mode

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I’ve not updated the blog for a few months, but its doesn’t mean that nothing has happened in solar science. I’ve just been doing other things, OK?

I’m going to be sending through a large number of posts in the next few days and weeks, as there have been a lot of conflicting signals about whether Solar Cycle 24 has really turned up or not, about whether the Sun has gone into hibernation or not, about the effects on the Earth’s climate (or not).

Be back shortly.

Written by John A

October 1, 2008 at 12:45 pm

Posted in News and Views