After I posted the video of the solar eruption earlier this week, I got a lot of questions about why material fell back from the explosion onto the Sun. The quick answer: gravity! A lot of the material from a prominence like that falls back onto the Sun because of the Sun's strong gravity. Since the material is an ionized plasma - a gas stripped of one or more electrons -- it follows the magnetic field lines of the Sun, so you can see graceful arcs of this stuff falling back down after the blast (see Related Posts below for links to more detailed descriptions of this phenomenon). Oh, why describe it when I can show you? This video is from the NASA/JAXA Hinode spacecraft which observes X-rays from the Sun. It caught the event in loving detail:
[embed width="610"]http://www.youtube.com/watch?feature=player_embedded&v=-sZcJyyHAMI[/embed]
See? Gravity does the work, but magnetism does the steering.
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