[SFDXA] Solar Cycle 25 is more active and powerful than predicted

Bill bmarx at bellsouth.net
Wed Aug 16 09:21:33 EDT 2023


> <https://earthsky.org/sun/>
>
>
>   Solar Cycle 25 is more active and powerful than predicted
>
> Posted by
> EarthSky Voices
> <https://earthsky.org/author/earthskyblog/>
> August 16, 2023
> Partial view of mottled red and orange sun with yellow explosion 
> coming out of it.A coronal mass ejection, or CME 
> <https://earthsky.org/sun/what-are-coronal-mass-ejections/>, on the 
> sun’s surface is a frequent occurrence during the current active solar 
> cycle, Solar Cycle 25 
> <https://earthsky.org/sun/solar-cycle-25-news-and-updates/>. Image via 
> NASA 
> <https://images.theconversation.com/files/541795/original/file-20230808-15-85ytq4.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C1920%2C1080&q=45&auto=format&w=754&fit=clip>/ 
> GSFC/ SDO.
>
> By Daniel Billett 
> <https://theconversation.com/profiles/daniel-billett-1454153>, 
> University of Saskatchewan 
> <https://theconversation.com/institutions/university-of-saskatchewan-1403>
>
> What do you feel when you see the aurora?
>
> Otherwise known as the northern or southern lights, an aurora is light 
> emitted by upper atmospheric particles as they interact with energized 
> ones from the magnetosphere <https://superdarn.ca/tutorials-11>.
>
> It’s an awe-inspiring and otherworldly event that those living at high 
> latitudes can experience often. In Cree and Ojibwe teachings 
> <https://creeliteracy.org/2018/05/01/northern-lights-creesimonsays/>, 
> the northern lights are ancestral spirits who remain and communicate 
> from the sky.
>
> To scientists, the aurora is an infinitely complex amalgamation of 
> ionospheric <https://www.nasa.gov/ionosphere> dynamics, a 
> manifestation of Earth’s intrinsic connection to the sun. To industry, 
> it’s a risk factor.
>
> Keep track of sun news with EarthSky’s daily sun post 
> <https://earthsky.org/sun/sun-activity-solar-flare-cme-aurora-updates/>.
>
> Tall, ribbon-like green light in the sky above powerlines. 
> <https://images.theconversation.com/files/540229/original/file-20230731-17-9pbazi.jpg?ixlib=rb-1.1.0&rect=0%2C2%2C936%2C524&q=45&auto=format&w=1000&fit=clip>The 
> aurora borealis seen above the Saskatoon SuperDARN space weather 
> radar. Image via A. Reimer.
>
>
>       The Starlink destruction event
>
> In February 2022, SpaceX launched 49 Starlink internet satellites into 
> a low-Earth orbit <https://www.bbc.com/news/world-60317806>. This was 
> the 36th Starlink launch that SpaceX had carried out, and one that 
> they anticipated to go off without a hitch, just like the 35 before.
>
> On launch day, a coronal mass ejection 
> <https://www.swpc.noaa.gov/phenomena/coronal-mass-ejections> – a large 
> burst of plasma expelled from the sun – struck Earth. It caused a 
> geomagnetic storm in the atmosphere between around 62 and 310 miles 
> (100 and 500 kilometers) in altitude, the target range for Starlink.
>
> This event injected an immense amount of electromagnetic energy 
> straight into Earth’s upper atmosphere. It produced beautiful auroral 
> displays <https://www.youtube.com/watch?v=q_GYySXTtio>. But the energy 
> also increased the density of the air. A higher air density typically 
> isn’t a big deal for satellites in low-Earth orbit, because it’s 
> already extremely low at usual operational altitudes (upwards of 248 
> miles or 400 kilometers).
>
> Starlink, however, was initially launched into an altitude of 130 
> miles (210 kilometers) <https://doi.org/10.1029/2022SW003074>. That’s 
> much closer to Earth, with an exponentially higher air density. 
> Thirty-eight out of those 49 initial launch satellites were 
> subsequently lost due to atmospheric drag from the dense atmosphere, 
> pulling them back to Earth <https://doi.org/10.1051/swsc/2022034>.
>
> Starlink satellites burning up in the atmosphere over Puerto Rico, 
> Feb. 7, 2022.
>
>
>       Surprising solar cycle
>
> The sun undergoes a cycle – an 11-year one, to be exact – from which 
> its activity increases and decreases periodically. At the peak of a 
> cycle, we see more sunspots on the solar surface, more radiation 
> emitted, and more solar flares. Geomagnetic storms like the one that 
> caused the Starlink destruction event are a relatively common 
> occurrence, especially when the sun reaches the peak of its 11-year 
> cycle of strengthening and weakening activity.
>
> In the previous cycle, which ended in 2019 (the 24th tracked cycle 
> since 1755), there were 927 storms classed as moderate or weak alone 
> <https://doi.org/10.1016/j.asr.2022.10.033>, an average of one every 
> five or so days.
>
> We’re currently four years into Solar Cycle 25, but this one has 
> already proven surprising. The maximum activity of the 25th cycle was 
> predicted to occur in 2025. But solar activity has already exceeded 
> the expected maximum. This means we’ve been seeing more geomagnetic 
> storms, more auroral displays (and at lower latitudes than usual) and, 
> potentially, more hazardous conditions for satellites in low-Earth orbit.
>
> Graph, with a jagged line corresponding to a gray sine wave, but 
> steeper than the rightmost wave. 
> <https://images.theconversation.com/files/540308/original/file-20230731-23-cwg668.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip>Solar 
> activity as the number of sunspots visible on the solar surface. The 
> number of sunspots seen is already considerably higher than what is 
> expected from the solar maximum, two years ahead of schedule. Image 
> via National Oceanic and Atmospheric Administration 
> <https://www.swpc.noaa.gov/products/solar-cycle-progression> (NOAA).
>
>
>       Space weather — the unseen force of nature
>
> If geomagnetic storms are so common, why don’t they cause more issues? 
> The reality is that they do 
> <https://www.maine.gov/mema/maine-prepares/preparedness-library/geomagnetic-storms>, 
> but the consequences are much less obvious than satellites burning up 
> in the atmosphere.
>
> When space weather energy enters Earth’s upper atmosphere, for 
> example, the ionospheric composition changes in addition to the air 
> getting denser. High-frequency, or “shortwave,” radio communication 
> depends on a predictable ionosphere to broadcast long distances.
>
> Geomagnetic storms that affect ionospheric composition can cause radio 
> blackouts <https://doi.org/10.1029/2018SW002008>, such as a disruption 
> in North America on August 7 
> <https://www.space.com/x-class-solar-flare-radio-blackout-august-2023>. 
> Even minor storms can cause the degradation of radio signals used in 
> military and maritime systems, aviation communication or ham radio.
>
> Extreme storms can cause radio blackouts lasting hours, and for an 
> entire side of the globe. Storms that big can also cause more 
> discernible problems, such as the nine-hour electricity outage 
> experienced by Hydro-Québec in 1989 
> <http://www.hydroquebec.com/learning/notions-de-base/tempete-mars-1989.html>.
>
>
>       Space weather warning systems
>
> It’s not all doom and disintegrating rockets, however. We can detect 
> when a solar flare leaves the surface of the sun and predict roughly 
> when it will affect the Earth, giving forewarning to certain types of 
> storms and chances to see the aurora <https://www.aurorawatch.ca/>.
>
> For many storms however, there is very little or no predictive 
> capability because it depends on how the Earth’s magnetic field 
> interacts with the solar wind, which is harder to see.
>
> Nowcasting — using real-time data to understand conditions as they 
> occur — is one of our best tools. With instruments such as 
> ground-based radar and magnetometers on satellites, we can estimate 
> the electromagnetic space weather energy entering the atmosphere 
> almost instantaneously <https://doi.org/10.1029/2023GL103733>.
>
> As for why SpaceX lost satellites in February 2022 during a minor 
> geomagnetic storm, that was just a matter of timing. The loss of the 
> satellites, however, is a stunning reminder of the power of the 
> universe we live in.The Conversation
>
> Daniel Billett 
> <https://theconversation.com/profiles/daniel-billett-1454153>, 
> Postdoctoral Fellow in Space Physics, University of Saskatchewan 
> <https://theconversation.com/institutions/university-of-saskatchewan-1403>.
>
> This article is republished from The Conversation 
> <https://theconversation.com> under a Creative Commons license. Read 
> the original article 
> <https://theconversation.com/this-solar-cycle-the-suns-activity-is-more-powerful-and-surprising-than-predicted-209955>.
>
> Bottom line: Daniel Billett discusses how the current solar cycle has 
> been surprisingly active even before reaching the expected peak in 2025.
>
https://earthsky.org/sun/solar-cycle-25-more-acitve-powerful-than-predicted/?mc_cid=dfbdd1ee7e&mc_eid=fbac876af9
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/sfdxa/attachments/20230816/47a853d8/attachment-0001.html>


More information about the SFDXA mailing list