Solar Activity | Types | Impacts on Earth

The Sun is a very busy place. Close inspection through telescopes such as the New Solar Telescope at Big Bear Solar Observatory in California reveals a surface roiling with activity.

New Solar Telescope | Big Bear Solar Observatory

Types of Activity 

Sunspots There are regions where the temperature is somewhat cooler than the surroundings. These show as darker and are known as sunspots. Four Earths would fit in the dark center of this sunspot. They are not cool by any means. The yellow area is 5800 Kelvin (9980˚F). The sunspot is 3800 K (6380˚F).

New Solar Telescope | Big Bear Solar Observatory

Sunspots are associated with the magnetic activity of the Sun. The magnetic field of the Sun is not stable or static like that of a permanent magnet. Because of the circulation of huge currents of charged particles within the Sun, the strengths and directions of the magnetic field are continuously changing. Flares Often, there are eruptions of the magnetic field at the surface causing flares to rise and dance. Some of the flares extend out into space as prominences. These are not energetic enough to cause noticeable effects here on Earth.

Solar Dynamics Observatory | http://sdo.gsfc.nasa.gov/

CME Some rare eruptions can be accompanied by a huge burst of light and radiation whereby a large cloud of solar material is ejected at high speed from the Sun. These are called Coronal Mass Ejections (CME). If they are aimed at Earth, they can have significant effects on power grids, satellites, and auroral activity several days later. Scientists monitor these enormous space weather events for geomagnetic storms, solar radiation storms, and radio blackouts. The difference between flares and CMEs is visually described by this 2 minute NASA video.


CME Effects On Earth

Geomagnetic Storms The most common form of space weather effect on Earth is the geomagnetic storm. Earth is protected by a sheath of magnetic field called the magnetosphere. Our magnetosphere guides energetic particles around Earth. Normally, it is quiet and relatively stable. This video models the protective nature of the magnetosphere of Earth. The Sun is off to the left out of view. At about 20 seconds, there is an increase in activity from the Sun due to a CME. By 30 seconds, the activity begins to subside to normal. The magnetic field lines of Earth point northward as indicated by a compass. The interactions of a CME with the Earth’s magnetosphere can cause damaging effects. Storms are categorized from G1 (minor) to G5 (extreme). In the most extreme cases transformers in power grids may be damaged, spacecraft operation and satellite tracking can be hindered, high frequency radio propagation and satellite navigation systems can be blocked. Aurorae may appear much further south than normal. A CME travels with its own magnetic field. They connect with the field of the Earth on the outside of the magnetosphere for a period of time. If the CME field lines up with Earth’s field, the energy and the charged particles slide around the Earth and cause little change. If the CME field is opposite of Earth’s field, the disturbance can be dramatic and visual. Charged particles can be caught up in the magnetosphere. The shape of the magnetosphere changes. The particles follow the Earth’s field lines into the polar regions as a sort of loop, or ring of aurora. These energetic particles excite the gases in the upper atmosphere and cause them to emit characteristic colors of green, red, and purple hues. This is a common event over the Canadian provinces and similar latitudes around the world both north and south. Sometimes they appear at lower latitudes across the United States as on March 17, 2015. Solar Radiation Storms A solar radiation storm, also called a solar energetic particle (SEP) event, is an intense inflow of radiation of protons and other charged particles from the Sun. The radiation is blocked by the magnetosphere and atmosphere and cannot reach humans on Earth. It could harm humans traveling during spaceflight from Earth to the Moon or Mars. It has little to no effect on airplane passengers or astronauts within Earth’s magnetosphere. Solar radiation storms can also disturb the regions where high frequency radio communications travel. During an SEP, airplanes traveling routes near the poles which rely exclusively on radio communications may be re-routed. Solar radiation storms are rated on a scale from S1 (minor) to S5 (extreme), determined by how many very energetic, fast solar particles move through a given space in the atmosphere. At their most extreme, solar radiation storms can cause complete high frequency radio blackouts, damage to electronics, memory and imaging systems on satellites, and radiation poisoning to astronauts who might be outside of Earth’s magnetosphere. The ISS is not that far away. Radio Blackouts Radio blackouts can occur when the strong, sudden burst of x-rays from a solar flare hits Earth’s atmosphere. These can jam high and low frequency radio signals. The X-rays disturb a layer of Earth’s atmosphere known as the ionosphere, through which radio waves travel. The disruptions to the ionosphere change the paths of the radio waves and degrade the information they carry. The loss of low frequency radio communication causes GPS measurements to be off by up to several miles. They can also affect the applications that govern satellite positioning. Radio blackouts are rated on a scale from R1 (minor) to R5 (extreme). The strongest radio blackouts can result in no radio communication and faulty GPS for hours at a time.


Solar activity increased until about 2013 and then decreased slightly. It has increased since. The trend is predicted to decrease over the next few years to a minimum. The cycle will begin again as is has about every 11 years. Fortunately, we don’t appear to have any direct harmful effects to worry about here on the ground. Indirectly, the solar storms and CME could cause a lot of havoc if they are intense enough to disrupt power grids or communication systems. Alerts are issued when activity warrants. You can check the current space weather conditions at this link.

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34 thoughts on “Solar Activity | Types | Impacts on Earth

  1. It strikes me that when we are looking at our planet and how it works in relation to the sun and stars, it is so full of complexity that it amazes me. Actually, it terrifies me…what would it take to knock us out of orbit, and what would happen? To my mind, who needs science fiction when you have science? Thank you for this fascinating post, Jim.
    Did you get more snow? We did. I’m still hoping for that thunderstorm to come our way…

    Liked by 1 person

    • Science is more amazing that SF in my book.

      Out of orbit? It would take a collision with something massive like a big asteroid near the size of the moon. None of those are headed our way. They are being tracked.

      No snow. Just a little rain. I did hear thunder a few days ago before dawn. I liked that. Today is clear and windy.

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      • I didn’t express myself quite the way I wanted to. What I meant was, most of us don’t know or think about all the complex things that are going on with our sun. We don’t begin to grasp all of the things that could affect our planet~things that can interact with our climate, etc. I read once about how our planet is tipped just so, and that catastrophic things could happen with just a little more or less tilt. It terrified me to think the galaxy could all be like a house of cards. Is this what agoraphobia is like, I wonder? I mean, I know that the whole thing isn’t going to fall apart. yet…
        I like hearing thunder, too. 🙂

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      • There is no end to the intricacies of the natural world. You see many of them in your paintings. There are relationships on so many different levels. Many we are barely aware of, if at all. It is an adventure to find out new things.

        I predict you will hear thunder one of these days.

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      • Hmmm… speaking of asteroids and the moon, have you seen this?

        Something else that really interests me is the weakening of the magnetic field, and the potential for a flip. I don’t expect it any time soon, but it’s good to be prepared.

        I see boats out in the bay or channel every now and then that clearly are “swinging their compass,” doing the compensation necessary with a magnetic compass. For whatever reason, figuring out true north and magnetic north was hard for me when I started learning to navigate. But my goodness — it can make a difference if you get them confused!

        Liked by 1 person

      • I did see that story. I think is sounds very interesting. Large masses could be captured in lunar orbit without the need to bring them all the way to Earth. It would be safer.

        The magnetic field will flip some time. It will probably take a while to happen. Meanwhile, the poles are moving around each year. Keep your compass aligned and don’t get lost.

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  2. So the ‘Northern Lights’ are really Coronal Mass Ejections (CME) from the sun? Fascinating. I still don’t understand much about “magnetism” and its pull towards the ‘north’. I suppose it’s related to gravity. Why is it called ‘Earth’s magnetosphere’? in the first place?

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      • Thanks Jim, and I did read the link you provided about “magnetosphere”, but if you can explain it in terms of what does the magnetism respond to. I know it’s like a protective layer, but it responds to something else, doesn’t it?

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      • Magnetic fields are caused by the motion of moving charges.
        Magnetic fields respond to other magnetic fields. You’ve seen it with bar magnets.
        M-fields respond to certain metals like iron.
        M-fields cause charged particles moving through them to be steered off course in curving paths.

        We need to sit down over coffee and talk this over. 🙂

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      • I just read in the ‘magnetic field’ link shoreacres provided that the field exists because Earth has a giant ball of iron at its core surrounded by an outer layer of molten metal. Changes in the core’s temperature and Earth’s rotation boil and swirl the liquid metal around in the outer core, creating magnetic field lines. How does this relate to the moon, however.

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      • You aren’t driving me crazy. One of the reasons I blog is to engage in some interaction with readers. We teachers like that sort of thing. 🙂

        A bit of a correction…the moon is moving farther away due to the action of the tides and gravity, not magnetism. Since the distance from earth is increasing, the stirring referred to in the article would be decreased, having less ability to cause magnetic effects.

        The planet orbits are not circles, rather are a little eccentric. Their distances from the sun vary a little as they orbit. But, over the billions of years, they haven’t changed distance. Naturally, the distances to other planets is continually changing. But, the range of closest to farthest hasn’t really changed over time.

        I hope that helps. You know where to find me if others come to mind.

        Liked by 1 person

      • It is happening slowly all the time. Here is an article that answers your question. Billions of years from now…

        “…the day and month (will) both equal about 47 (current) days, billions of years in the future. If the Earth and Moon still exist, the distance will have increased to about 135% of its current value.”

        Now we are affected by adding a second to our clocks every few years. Not a big deal. It builds up over time, but slowly.

        http://www.physlink.com/Education/AskExperts/ae429.cfm

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      • “Once the length of a day equals the length of a month, the tidal friction mechanism would cease.” So once the tidal friction ceases, what would happen to the oceans?

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      • No more tides. Well…not really true. No more tides caused by the moon. Those caused by the sun would still be present. But, they are a lot smaller in size.

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