Transcription
Hey folks, we are often asked what causes sunspots and coronal holes to appear. Yesterday, we went over the differences in those features. Where here in UV light, the coronal holes look dark and the sunspots are very bright. But what causes them to show up in the first place?
Well, the first thing we have to know is that there are cycles that affect them: Sunspot maximum and Sunspot minimum. During the Sunspot minimum, there are very few sunspots, if any at all, and also there are fewer equatorial coronal holes. During the maximum of the Sunspot Cycle, there are lots of sunspots and the coronal holes are more likely to be seen near the sun's equator.
But why is that? Is there a connection between the sun's 11-year cycle, sunspots, and coronal holes? Yes, there is. The same processes that trigger the higher eruptive activity on the sun, often coming from those sunspots, is the same process that delivers coronal holes to lower latitudes. This process is the solar polar magnetic field reversal.
The sun's magnetic fields reverse every 11 years. The polar magnetic fields completely switch sides on the sun, but it doesn't happen in a day. It happens over several years, the sunspot maximum years to be exact. Let's compare.
During Sunspot minimum, the polar fields are calmly set at the polar region, and the coronal holes are prominently at the polar region as well. There are no bright sunspots, and the coronal holes again are largely confined only to that polar region.
But during Sunspot maximum, that begins to shift. As the polar magnetic fields of the sun reverse and cross the equator, they do so within the coronal hole structures, and the bright sunspots appear as well. It is this magnetic field reversal again, across the equator from the polar region, that triggers both the appearance of the sunspots and the lower latitude positioning of the coronal holes.
As those fields are reversing across the equator, they blow out the coronal particles as enhanced solar wind, which is why the coronal holes leave the polar region and appear at lower latitudes. Exactly at the same time as those fields are reversing, and the disruption to the sun's surface layer caused by the magnetic reversal is why we get the sunspots, which are powerfully magnetic areas in and of themselves, which often unleash electromagnetic solar flares.
For now, just know that it isn't a coincidence. These items are related, and it's all driven by the cyclical magnetic reversal on our sun. It's an enduring feature of spinning objects in space. Most of you know the Earth has magnetic flips as well. In fact, we're in the beginning stages of one right now. And they have even seen this happen at the galactic level. Interestingly, they noticed the galactic version when the central engine of the galaxy had a major eruptive outburst during the reversal, just like the sun has from sunspots during its reversal, and just like Earth's volcanoes have been shown to always have upticks during magnetic flips here on our planet.
Magnetic reversals, sunspots, coronal holes, eruptive activity. I hope this was helpful. I'll see you in the morning for The Daily Show. Be safe, everyone.