Time for the monthly sunspot update: NOAA yesterday released its the monthly update for the Sun’s sunspot cycle, adding sunspot activity for April 2019 to its graph. As I do every month, I have annotated that graph to give it some context and am posting it below.
While the Sun is clearly at the beginning of what might be an extended or very extended solar minimum, the continuing uptick in activity in both March and April illustrates that we have still not arrived at full minimum.
The graph above has been modified to show the predictions of the solar science community for the previous solar maximum. 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, extended in November 2018 four years into the future.
As the Sun ramps down to minimum it will have months where there is no activity, as happened in February 2019, and months, such as in March and April, where more sunspots appear.
Eventually the quiet months will become dominate, and soon thereafter, when activity increases again (assuming it does), the solar science community will then announce the date of true minimum.
We are not there. Normally it can take a year or more for the Sun to settle down. If activity declines as indicated by the red curve, it could take as long four years, which would be a record-long minimum. The difference will tell us whether the eleven-year solar cycle is continuing, or the Sun is heading into a grand minimum, with no significant sunspots for decades.
And as I have said repeatedly in the past five years, a grand minimum could significantly impact the global climate, cooling it. Or not. It is that unknown that will be answered should a grand minimum occur. Circumstantial data suggests an inactive Sun cools the planet, and the arrival of a new grand minimum will allow scientists to confirm or refute that circumstantial data.
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. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
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