[GAS] Science Class: The Sun and Solar Flares

Good morning, Geeks. Please take your seats.

Today we’ll discuss the science behind solar flares and the distinction between a flare and coronal mass ejections. By now you’ve all seen the images and video from Tuesday’s M2.5 flare and CME. What you may not have gotten is a look at what solar flares actually are and how they’re produced. So that’s what we’ll work through this week.

What’s up, Sun?

In order to appreciate the  massive plumes of energy flying from the sun’s surface, you first have to have a basic understanding of what’s going on inside.

In the beginning, there was a nebula (or molecular cloud or interstellar gas cloud) composed primarily of hydrogen and helium. The cloud collapsed and during this process, sectioned into smaller portions which pulled themselves together to form stars. Our sun’s particular area was massive enough to reach 10 million Kelvin, initiating the production of deuterium–nuclear fusion.

Finally–after much spinning and heating and nuclear fusion and the birth of eight planets (sorry, Pluto)–following the stars’ aging process, stellar maturity, our sun is now 4.6 billion years old and a class G2 star, just like Alpha Centauri A.

Like any rotating body composed of multiple materials, the sun has layers of varying composition and temperature. From the interior outward, the sun comprises a core, radiative zone, and convective zone. The sun’s atmosphere is composed of the chromosphere, photosphere and corona (again, from the inside out).

There’s a “dynamo” joke in here somewhere.

According to the Solar Dynamo Theory (the generally accepted but still slightly flawed idea of what’s going on in there), the fun stuff starts in the convective zone, where–through convection–plasma is boiling around while the sun spins. This rotating plasma is a really good electrical conductor, which means it can build up an electromagnetic field from magnetism already present in the materials. Remember the nebula we discussed? Interstellar gas clouds have magnetic properties; the theory works if we assume that part of that magnetic field was still present when the cloud coalesced during the initial phases of star production.

The magnetic field of the sun and the majority of other stars is most concentrated at the equator. Bands of magnetic “flux ropes” wrap around the sun’s middle, causing areas of high magnetic activity, the source of all solar weather: solar wind, sunspots, solar flares and coronal mass ejections.

We need to talk about your flare.

There’s a misconception that needs to be cleared up before we go any further. A solar flare is the sudden release of energy from the sun; a coronal mass ejection (CME) is a burst of plasma from the sun. These events are sometimes interconnected, though the understanding of their relationship is not well established, but it’s important to know the difference.

A solar flare is defined as a sudden, rapid, and intense variation in brightness that occurs when magnetic energy built up in the solar atmosphere is suddenly released. All three layers of the atmosphere are affected when plasma is heated and electrons, protons, and heavier ions are accelerated nearly to the speed of light. Solar flares produce radiation at all wavelengths, from radio waves to gamma rays.

Coronal mass ejections are massive burst of solar wind, other light isotope plasma, and magnetic fields rising above the corona or being released into space. The ejected material is plasma consisting primarily of electrons and protons; sometimes, the CME can contain small quantities of helium, oxygen, and iron.

Tuesday’s widely-discussed solar event was the combination of a medium-sized solar flare and a really massive CME. It was the largest solar explosion ever witnessed, but the flare itself was fairly unremarkable. The surprise (and awesome video) comes from the CME, a feature which astrophysicist Phillip Chamberlin, of NASA’s Solar Dynamics Observatory (SDO), says, “We’ve never seen a CME this enormous.”

Here’s the footage again in the most theatrical version available.

Further reading:

[sources: 1|2|3|4|5] [images: 1|2]

OK, so that was the first of the “thinky topics”  posts. Yea? Nay? Weigh in, Geeks.

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27 Responses to [GAS] Science Class: The Sun and Solar Flares

  1. There's a "Like" button here, somewhere, right? Topic: current, Video: excellent, Writing: superb as expected
    The only thing that was missing, for me, was understanding if there was any kind of implication for my d2d life as a result of a CME of this magnitude.
    Kudos on a fabulous premier. I look forward to next class!

    • The position of Earth in relation to the CME saved us all this time. At best we got some great aurora from this, and at worst anyone hanging out in the ionosphere now has skin cancer. (I don't think anyone is up there.) :P

    • They actually do have an impact on daily life for most people.  To us satellite operators, those things are bad news, what with the initial CME Proton event ( which arrives roughly 20 minutes after a CME), and then the bombardment of solar materials that follow behind it (Solar material and magnetic fields about 1-4 days behind the proton event and also the part that causes really big auroras) can damage and even decommission the satellites- especially ones not under the protection of Van Allen radiation belts (thats the name of the giant magnetic bands that surround the earth and shield them from most of the Sun's harmful effects).

      Auroras are pretty, but they also might mean your Sirius Radio or GPS wont work for a while, and considering how many people use GPS, that would be some kind of disaster.

      • All true! I should have been more specific in my reply, which was in reference to this specific CME. All the reports I've read suggest that because of the location of the event in relation to Earth, we escaped the majority of solar weather's ill effects. I'm interested, though, in what, if anything, did fall victim to this recent CME's blow. Did you experience any outages or interruption?

      • All true! I should have been more specific in my reply, which was in reference to this specific CME. All the reports I’ve read suggest that because of the location of the event in relation to Earth, we escaped the majority of solar weather’s ill effects. I’m interested, though, in what, if anything, did fall victim to this recent CME’s blow. Did you experience any outages or interruption?

  2. I am liking the "thinky topic". The writing was well done, and I appreciate the further reading links. I would also like to know if this CME will have any effect on us though. Looking forward to the next one! 

    • The plasma from a CME tends to fall back into the star (it, unlike the EM waves released in a Flare, has a considerable mass – more so than than the few particles that accompany a Flare, and it is highly charged, so it gets grabbed by the star's magnetic field), but if it the plasma, or a portion of plasma, achieves it's escape velocity (and happens to be on the right trajectory), then it could cause fluctuations in a planet's magnetosphere and cause some spectacular Auroras.
      Those arches you see come out of a star (what you think of, when you think "Solar Flare") are actually CMEs, but the CMEs usually happen with Flares as welll – Flares being something you can't see with the naked eye as they are pure EM radiation stretching from Radio (the last visual of this CME/Flare was a radio image if I'm not mistaken) all the way up the frequency range to Gamma. The high the frequency (i.e. Gamma Radiation), the more dangerous it is.

  3. As I was watching the video, I was kind of expecting something bigger. Then it clicked as to how big that was in terms of the size of the sun, and how big the sun is compared to everything else… I feel very small, now :P

  4. Brilliant article!  I am so glad that [GAS] heard how much we loved the site and how much we love science.  I sent in a comment about how I am an International Science teacher and that I use websites, twitter, facebook etc to provide my students with more engaging and in depth knowledge on what we are studying.  There is so much more available to me as a teacher that I am now able to show students far more than I could ever have imagined (although I am still early in my teaching career).  This article ties in wonderfully with both my Earth Science class (perfect timing as their finals are next week) and my 7th grade science class (who are studying space right now).  Thank you so much for giving me even more to share with my students.  With sites like [GAS] the love to learning, technology and science grows every day.  Keep up the great work!

  5. Brilliant article!  I am so glad that [GAS] heard how much we loved the site and how much we love science.  I sent in a comment about how I am an International Science teacher and that I use websites, twitter, facebook etc to provide my students with more engaging and in depth knowledge on what we are studying.  There is so much more available to me as a teacher that I am now able to show students far more than I could ever have imagined (although I am still early in my teaching career).  This article ties in wonderfully with both my Earth Science class (perfect timing as their finals are next week) and my 7th grade science class (who are studying space right now).  Thank you so much for giving me even more to share with my students.  With sites like [GAS] the love to learning, technology and science grows every day.  Keep up the great work!

  6. Wonderful! Isn't the best part of beeing a geek going to bed knowing you're a little less stupid than you were when you woke up?! Moar of this.