The Sun is very quiet at the moment – there have been 22 spotless days in a row. This year out of 269 days which have passed – which unfortunately reminds it that it is only 90 days to Christmas – there have been 193 days or days without spots. Last year there were 221 days without spots. So we are very obviously in a solar minimum. So what does that actually all mean and why does it matter?
It looks as if Southern Hemisphere winter of 2019 go down in history as “the winter without sunspots”?
From June 21st until Sept 22nd, the sun was blank more than 89% of the time. During the entire season only 6 tiny sunspots briefly appeared, often fading so quickly that some observers did not see and therefore siding not count them.
Also there wasn’t a single significant solar flare was detected during this period of extreme quiet.
The sun on September 23, 2019–as blank as a billiard ball. Credit: NASA/SDO
This is a sign that Solar Minimum is underway and probably near its deepest point.
For 2019 overall (January through September), the sun has been blank 72% of the time, comparable to annual averages during the deep solar minimums of 2008 (73%) and 2009 (71%). These were classed as Century class solar minimums. The current Solar Minimum appears to be century-class as well, meaning you have to go back to the beginning of the 20th century to find lulls in solar activity this deep. Which interestingly coincides with the Federation’s drought. And at the risk of being controversial – I have been finding some interesting correlations between very deep minimums and drought conditions – this of course has been put forward by others but since this is a topic I am very interested in – I am doing a lot of reading and studying up on at present.
So what actually is going on during these times known as a “Solar Minimum”. Well the Sun is not being boring. During this particular phase of the solar cycle, the magnetic field of the Sun weakens. This allows cosmic rays the solar system. This could possibly increase the amount of radiation affecting astronauts in the Space Station.
The Sun seems to dim a little during these times party at extreme ultraviolet wavelengths, which causes the upper atmosphere to cool and contract. Space junk accumulates in Earth orbit as a result. Finally, streams of solar wind are able to break through Sun’s weakening magnetic field, and so lash the Earth with gaseous material that can cause geomagnetic storms. (One such stream is due later this week on September 27-28). This is when if you located suitably you have the opportunity to see auroras.
Interestingly, the winter of 2019 also brought us a sign that Solar Minimum is coming to an end. One of the numbered sunspots that briefly appeared on July 7th had a reversed magnetic polarity:
So, if the sun really is entering an unfamiliar phase of the solar cycle, such as that similar to the Maunder Minimum of the late 17th-early 18th century and the coldest part of the Little Ice Age we really need to improve our understanding of the Sun-climate link.
According to Hale’s Law, sunspots switch polarities from one solar cycle to the next.
One of the most recent small sunspots was +/- instead of the usual -/+, marking it as a member of the next solar cycle, Solar Cycle 25. Solar Minimum won’t last forever! And dare I say it – neither will this drought.
Solar cycles always mix together at their boundaries. We can expect to see more new-cycle sunspots in the months ahead as Solar Cycle 24 dies out and Solar Cycle 25 slowly comes to life. If forecasters are correct, the next Solar Maximum will be in full swing by 2023.