By Lina Tran, Karen Fox, NASA’s Goddard Space Flight Center
On the left side of the picture from May 29, 2020, from NASA’s Solar Dynamics Observatory — shown one can see a spot of light hovering above the left horizon. This light emanates from solar material tracing out magnetic field lines which are hovering over a set of sunspots about to rotate the side of the Sun across.
A family of sunspots spots which freckle the face of the sun, representing regions of complicated fields–sported the solar flare since October 2017. Even though the sunspots aren’t yet visible (they will soon rotate into view over the left side of the sun), NASA spacecraft seen the flares high above them.
The flares were too weak to pass the threshold at which NOAA’s Space Weather Prediction Center (that will be the U.S. government’s official source for space weather forecasts, watches, warnings and alarms ) provides alerts. But after a few months of very few sunspots and solar activity, scientists and space weather forecasters are currently keeping their eye to see if they grow or quickly disappear. The sunspots may be harbingers of the solar cycle getting more active and ramping up of the sun.
Or they might not. Before we know for sure it will be a few months.
As the sun goes through its natural cycle, in sunspots grow and fall in number, too. NASA and NOAA track the improvement of the solar cycle order predict, and to determine — and ultimately activity for sunspots. Currently, scientists are paying attention as it’s essential to discovering the dates of solar minimum, which is the beginning of Solar Cycle 25. This new sunspot activity might be a indication that the sunlight is revving up to the cycle that is and has passed through minimum.
It takes at least half a year of sunspot-counting and solar observations following a minimum whether it’s happened, to understand. Because that minimum is characterized by the lowest number of sunspots at a cycle, scientists need to see the numbers consistently rising before they could determine they had been in the base. That means minimum is recognizable in hindsight: It might take six to 12 months after the fact when minimum has actually passed, to affirm.
This is because our celebrity is very changeable. Just because the sunspot numbers go down or up at a given month does not mean it will not reverse route another month, only to return again the month after that. So, scientists want long-term data to build a picture of the sun’s overall tendencies . Commonly, that means the number we use to compare any given month will be that the average sunspot number from six months both backward and forward in time–meaning right now, we could characterize what October 2019 resembles in comparison with the months before it (there were fewer sunspots!) , but not yet what November seems like compared to that.
Solar flares are bursts of radiation. Radiation by a flare can not pass through Earth’s atmosphere to affect people on the ground when extreme enough — they could disturb the atmosphere where communications and GPS signals travel. The intensity of the flare was below the threshold for NOAA and below the threshold which could influence geomagnetic distance.
Yet, it had been the very first M-class flare since October 2017–and scientists will be watching to see if the sun is really beginning to awaken.