Tag: sun

Sunspots: A recovery in August

10:32 am

NOAA’s monthly update of the solar cycle was posted today. As I do every month, I am posting it here, with annotations to give it context.

August 2016 Solar Cycle graph

The graph above has been modified to show the predictions of the solar science community. The green curves show the community’s two original predictions from April 2007, with half the scientists predicting a very strong maximum and half predicting a weak one. The red curve is their revised May 2009 prediction.

The recovery in sunspot activity that began in July continued in August. The number of sunspots increased enough to once again raise the overall curve up to match the green curve of the 2007 weak prediction. Even so, this solar maximum remains far weaker than the weakest prediction. Also, this solar maximum, which started later than all the predictions, looks like it will be far shorter than all the predictions. As I have noted previously, this is counter to all previous solar cycles, where it is the more active cycles that are shorter and the weaker cycles are longer. Here, we are getting a weak cycle that is also short, which once again suggests that we are seeing solar behavior previously unobserved. The solar cycle is doing things it hasn’t done since scientists began studying it closely after Galileo.

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An update on Stereo-B’s status

12:04 am

The engineers working to recover Stereo-B, the solar observatory that was lost for 22 months, have released an update on the spacecraft’s condition.

In the subsequent days, analysis revealed the spacecraft was in a complex spin, with its fuel tanks frozen and the battery state of charge at 30%. The prime goal is now to fully recover battery power and gradually thaw STEREO-B’s instruments and fuel tanks from its deep freeze. It may be clear that the spacecraft is still in a critical condition and that it will take quite some time before imagery, such as those from its twin STEREO-A, will be available again.

If you are interested in more details, go to the Stereo-B update website, where they are posting almost daily reports.

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Contact re-established with dead solar satellite

5:43 pm

Good news! After almost two years since contact was lost, NASA has re-established communications with Stereo-B, one of two solar research satellites designed to study the hemisphere of the Sun that does not face the Earth.

NASA re-established contact with a wayward sun-watching science satellite Sunday nearly two years after the spacecraft suddenly dropped off line during a test, the agency said in a statement Monday. NASA’s Deep Space Network, or DSN, “established a lock on the STEREO-B (spacecraft’s) downlink carrier at 6:27 p.m. EDT,” NASA said in a statement. “The downlink signal was monitored by the Mission Operations team over several hours to characterize the attitude of the spacecraft and then transmitter high voltage was powered down to save battery power. “The STEREO Missions Operations team plans further recovery processes to assess observatory health, re-establish attitude control and evaluate all subsystems and instruments.”

This is a big deal. Not only is it a testament to the spacecraft’s good design, it demonstrates the skill of the engineers at NASA who have regained contact.

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Sunspot ramp down continues

9:36 am

Below is NOAA’s monthly update of the solar cycle, posted by them on August 7. It shows the Sun’s sunspot activity in July, with annotations.

July 2016 Solar Cycle graph

The graph above has been modified to show the predictions of the solar science community. The green curves show the community’s two original predictions from April 2007, with half the scientists predicting a very strong maximum and half predicting a weak one. The red curve is their revised May 2009 prediction.

As expected, there was a recovery in sunspot activity in July compared to June. Also as expected, the recovery was not significant, so that it appears, based on the past two months, as if the ramp down to solar minimum is accelerating so that solar minimum will occur sooner than expected, possibly as soon as two years.

I would not put much stock on that prediction, however. When sunspot activity first reached this level during the past solar cycle in late 2005, it still took three more years before solar minimum was reached. If this cycle matches the last, that would mean that this cycle, from minimum to minimum, will have lasted 10 years, making a short solar cycle though not one of the shortest. However, it is more likely that the ramp down will stretch out, as it usually does, gliding downward to solar minimum in a slow gentle curve that makes for a full cycle of about 11 years.

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SDO not returning data

8:55 am

For reasons that remain unexplained, the Solar Dynamics Observatory (SDO) did not return to science mode after it passed through the Moon’s shadow on August 2nd.

The only information about this on the SDO webpage simply states, ” The spacecraft did not go back into Science mode at the end of the transit. SDO FOT members are looking into the issue.” Spaceweather.com notes that “Since the transit no new data have appeared on SDO public websites.”

SDO has only been in orbit for six years. It would be a shame to lose it so quickly.

UPDATE: It appears that engineers are getting SDO back into operation. Hat tip James Fincannon.

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The Sun is blank again

2:01 pm

More signs that we are easing down to solar minimum: After a period of two weeks of sunspots, the Sun has once again gone blank.

It takes the Sun’s about four weeks to rotate and complete one “day”. What has essentially happened is that right now one face of the Sun is blank while the other face has sunspots. For two weeks, from the last week in June to the first week in July, the blank face was turned towards the Earth. Then the face with sunspots rotated into view for two weeks, and now the blank face has rotated back to face us.

Though new sunspots can always form on either face, I expect this blank stretch to last a few days, at least.

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A short but weak solar maximum?

3:03 pm

On July 4th NOAA released its monthly update of the solar cycle, showing the Sun’s sunspot activity in June. It is annotated and posted below.

June 2016 Solar Cycle graph

The graph above has been modified to show the predictions of the solar science community. The green curves show the community’s two original predictions from April 2007, with half the scientists predicting a very strong maximum and half predicting a weak one. The red curve is their revised May 2009 prediction.

Not surprisingly, the time periods with no sunspots in June, including a 12 day stretch that just ended today, is reflected by the graph’s precipitous drop in June.

What is significant to me is the speed with which this solar maximum seems to be ending. Normally, weak solar cycles are also long solar cycles. The Sun not only doesn’t get as active, but the ramp up and down is extended, as is the period of the solar minimum. This is what happened during the solar minimum from 2007 to 2010. It was longer than normal, which meant that the solar maximum occurred much later than predicted by the 2007 predictions of the solar science communities (shown in green).

This recent stretch of blank days however is now suggesting that the solar maximum is going to end much sooner than the later 2009 prediction (shown in red). Even more astonishing, the numbers in June aligned with the 2007 high prediction, which would make this one of the shortest solar maximums on record!

I don’t expect these low numbers to continue. I expect sunspot activity to recover and continue, with the minimum likely occurring after 2018. If it does come sooner, however, that will once again be evidence suggesting we are heading for a Grand Minimum, with no sunspots for decades.

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Sunspot cycle update

9:56 am

NOAA today released its monthly update of the solar cycle, showing the Sun’s sunspot activity in May. It is annotated and posted below.

Mayl 2016 Solar Cycle graph

The graph above has been modified to show the predictions of the solar science community. The green curves show the community’s two original predictions from April 2007, with half the scientists predicting a very strong maximum and half predicting a weak one. The red curve is their revised May 2009 prediction.

Though sunspot activity increased in May, the increase was not significant. The ramp down from solar maximum continues to track the 2007 low prediction for this maximum.

Meanwhile, the Sun continues its first multi-day string of blank days since 2011, now up to 3 days with all indications suggesting it will continue at least one more day. This early blank string, combined with the relatively fast decline in sunspots in the past two years, suggests that the solar maximum is ending sooner than predicted by the 2009 prediction (the red curve above), and that the next minimum will possibly be longer as well.

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