Sunspot update for May 2018: Solar activity hangs on


Genesis cover

On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.

 
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit.

 
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
 

"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs." --San Antonio Express-News

NOAA yesterday posted its monthly update of the solar cycle, covering sunspot activity for May 2018. As I do every month, I have annotated the graph and posted it below.

The small uptick in sunspots that we saw in April after the low in March continued.


May 2018 sunspot activity

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 yellow line compares the present activity with the activity during solar minimum in 2008 and 2009.

In a sense, the increased activity in May was less a return to an active Sun and more a reflection of the Sun’s 27-day rotation period. I have noted this previously but it bears repeating. We count sunspots by the number seen daily on the visible hemisphere of the Sun. Since it is not unusual for sunspot activity to be unevenly distributed across the entire solar globe, it often happens that, during the time when sunspot activity is weak but still occurring, one hemisphere will be blank while the other has sunspots. As the Sun rotates we therefore go through a two week period with no sunspots followed by a two week stretch with increased activity.

SILSO graph, June 4, 2018

This happened in May, as shown by the SILSO graph on the right. While a majority of the Sun’s surface had some sunspots in May, there was a week-long period mid-month when no sunspots were visible. It was at this time that the hemisphere that happened to be less active was facing us.

That quiet period ended on May 20th. Based on the Sun’s 27-day rotation period, you could then predict that a quiet period would next return around two weeks later, around June 1st. And lo and behold, if you look at the graph on the right you will see that on June 3rd the Sun returned to a blank state once again.

Obviously, this type of prediction is very superficial and explains nothing. Moreover, it is reliable only for short periods, as sunspot activity on the surface eventually shifts about so that no specific hemisphere of the Sun remains blank for long. Nonetheless, the fact that about half the Sun’s surface is now routinely blank is another indication that we are heading toward solar minimum, and it looks like we shall reach it, based on the first graph above, sometime late this year or early in 2019. This will make this solar cycle a short ten-year-long cycle. It will also be a weak cycle. This is unprecedented, as in the past short cycles were always more active, not less.

The Sun continues to baffle, and exhibit behavior that we have not seen in more than three hundred years, since the last Grand Minimum.

Readers!
 

My July fund-raiser for Behind the Black is now over. The support from my readers was unprecedented, making this July campaign the best ever, twice over. What a marvelous way to celebrate the website's tenth anniversary!
 

Thank you! The number of donations in July, and continuing now at the beginning of August, is too many for me to thank you all personally. Please forgive me by accepting my thank you here, in public, on the website.
 

If you did not donate or subscribe in July and still wish to, note that the tip jar remains available year round.


 

Regular readers can support Behind The Black with a contribution via paypal:

Or with a subscription with regular donations from your Paypal or credit card account:


 

If Paypal doesn't work for you, you can support Behind The Black directly by sending your donation by check, payable to Robert Zimmerman, to
 
Behind The Black
c/o Robert Zimmerman
P.O.Box 1262
Cortaro, AZ 85652

One comment

  • Phill O

    “Obviously, this type of prediction is very superficial and explains nothing.”

    Well, not quite true! It does explain the scatter in data near solar minimum, and that we need to remember that solar minimum has not yet come.

    However, the whole solar sun spot cycle is just one indicator for “something” is going on in solar dynamics. We are having a treasure trove of data right now, unprecedented in history: a possible chance to document what happens during a grand minimum.

    As with any research, as some questions are answered, many more come to “light”.

Leave a Reply

Your email address will not be published. Required fields are marked *