Why is it that when the outer planets align, we have fewer sunspots?
https://spaceplace.nasa.gov/solar-activity/en/
Sunspots are darker, cooler areas on the surface of the sun in a region called the photosphere.
The photosphere has a temperature of 5,800 degrees Kelvin. Sunspots have temperatures of about 3,800 degrees K. They look dark only in comparison with the brighter and hotter regions of the photosphere around them.
Sunspots can be very large, up to 50,000 kilometers in diameter.
They are caused by interactions with the Sun's magnetic field which are not fully understood. But a sunspot is somewhat like the cap on a soda bottle: shake it up, and you can generate a big eruption
. Sunspots occur over regions of intense magnetic activity, and when that energy is released, solar flares and big storms called coronal mass ejections erupt from sunspots.
http://solar-center.stanford.edu/FAQ/Qspotsearth.html
Sunspots are magnetic in nature. They are the places ("active regions")
where the Sun's magnetic field rises up from below the Sun's surface and those magnetic regions poke through. Sunspots are darker than the surrounding areas because they are expending less energy and have a lower temperature. Sunspots often have poles ("polarity") like the south and north poles of magnets.
Sunspots are formed continuously as the Sun's magnetic field actively moves through the Sun. The sunspots have lifetimes of days or perhaps one week or a few weeks.
Here is one scenario that some scientists think explains how sunspots form.
Imagine the magnetic field on the Sun as loops like rubber bands that wrap around the Sun, with one end attached to the south pole and the other end attached to the north pole. The Sun is rotating, and different parts of the Sun rotates at different speeds. As the Sun rotates, the magnetic loops wrap tigher and tighter (and get more and more twisted and complicated) until the magnetic field is wound up so tight that the fields ("rubber bands") snap! Where the magnetic field snaps is where active regions (and hence sunspots) on the Sun form.
https://www.iflscience.com/space/alignment-of-planets-may-explain-suns-mysterious-cycle/
The Sun's magnetic field influences many different Earthly phenomena, but we are not exactly sure how it works.
Now, a new theoretical study suggests a planetary alignment could play a crucial role in it.
Researchers from the Helmholtz-Zentrum Dresden-Rossendorf Association in Germany have looked at the potential influence that planets might have on the Sun. In their simulation, the team discovered that when Venus, Jupiter, and Earth are aligned, they produce a small but significant force on the Sun that leads to complex changes in its magnetic field.
We can imagine the Sun as an enormous dynamo. Stars are made of hot charged particles, the stellar plasma, and as they rotate on themselves these particles generate an intense magnetic field. The
solar dynamo is influenced by the interior structures of the Sun, and it is responsible for the famous sunspots, dark patches on the surface of the Sun. The dynamo’s polarity reverses with an 11-year cycle, which made scientists very curious.
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Obviously, the cause of Sun spots is magnetic field propagations and interactions. That is pretty certain.
And just as obviously the planets [particularly when aligned] will have an effect on the Sun, as well as does extrasolar planets have an effect on their own star/s. Afterall this is one of the methods of detecting extrasolar planets...They produce a tug on their star.
And while certainly the effects of tidal forces on the Sun, when planets are aligned, need be taken seriously, and their accumalitive effect on the Sun"and its magnetic fields,
it is essentially the magnetic fields that cause the Sunspots.
The same magnetic field lines are also thought to be the cause of the Sun's coronasphere being hotter then the surface.
Perhaps probes like the Parker solar probe and others specifically to study the Sun, will reveal more certainty about our home star.