Mar 16, 2012; 4:05 AM ET
This blog is written by AccuWeather Facebook page’s astronomy expert Daniel Vogler.
The other day, we witnessed something spectacular in my opinion, although the event is considered by most mainstream scientists a “coincidence.” I happen to believe there are no coincidences, we just have yet to figure out the reasoning behind them.
The event I am referring to is the Comet SWAN making it to its final destination that is the Sun and what happened after that. To see the comet again, click here.
A Coronal Mass Ejection was present nearly an hour or two later after the comet disappeared into the corona.
For a comet to have an effect on the Sun, it would require immense magnetic field strength. The comet itself does not have its own magnetic field, but it CAN get one as it gets closer to the sun. An induced magnetic field works like this: A comet’s most abundant ice species is the H2O water ice. As the comet gets closer to the sun, the ice sublimates, producing gas that trails behind it along with dust. It’s this setup that allows the mass ionization around the tail known as the ion tail. When you have ions, you then can have a magnetic field generating from the incoming solar wind from the sun. Once the particles have been ionized, they attain a net positive electrical charge. As the comet, now with its induced magnetic field, travels, a bow shock is formed. In this bow shock, large concentrations of cometary ions (called “pick-up ions”) congregate and act to “load” the solar magnetic field with plasma, such that the field lines “drape” around the comet forming the ion tail. (Carroll, B. W.; Ostlie, D. A. (1996). An Introduction to Modern Astrophysics. Addison-Wesley. pp. 864-874)
The addition of heavy cometary ions to the solar wind flow alters the dynamics due to the mass addition itself and also because the pick-up ions have a large pressure. The net effect is to slow down the solar wind. This slow-down process takes place continuously until a critical mass flux is reached, at which point a shock forms. (Galeev, A. A., Plasma processes in the outer coma, in Comets in the Post-Halley Era, vol. 2, eds. R. L.Newburn, Jr. et al., p. 1145, Kluwer Acad., Norwell, MA, 1991.)
Why am I being so technical with the vocabulary? If you haven’t figured out yet, the Sun’s own magnetic field is the main reason behind CMEs. And what would happen if something like a comet with an induced magnetic field that gets stronger, collecting plasma, as it gets closer to the Sun? My idea goes along the lines of the strength of the bow shock once it gets at the sun’s chromosphere, it generates enough magnetic force to shove each other and one will have to give, and since the sun is a gas star (albeit way bigger than the comet), the reaction comes from the other side (CME). Imagine trying to push two really big, like-sided magnets together.
I really hope this makes better sense as to how a comet gets a magnetic field and how this induced field is actually the culprit of the CME. Keep in mind, this is just a theory running around in my head with a few works cited on how the magnetic field is made. I have yet to see a real peer-reviewed study of this “coincidence.” If you have something to add to the theory that I may have not thought of, please like and comment on AccuWeather Astronomy on facebook for discussion.