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Astronomers Solve Magnetic Fields Mystery
An anonymous reader writes "It is a long-standing and unsolved mystery why 80% of all planetary nebulae are not spherical. Theories suggest that magnetic fields play a role in shaping planetary nebulae. A team of astronomers from Germany has now discovered the first direct clue that magnetic fields might indeed create these remarkable shapes. Planetary nebulae are expanding gas shells that are ejected by Sun-like stars at the end of their lifetimes."
If 80% aren't spherical one must ask why the other 20% are NOT.
Most (all?) photos you are likely to see of nebula are enhanced, and thus the colors generally vary depending on what the 'artist' (astronomer) was studying; colors that highlight differences in density will be used by the astronomer studying gas density, colors that accentuate gas temperature by the astronmer studying gas dynamics, etc.
That isn't to say your argument is wrong in anyway. I would agree with your hypothesis; however am not an expert in nebula dynamics in any way shape or form. I will state with great certainty that IF there are significate magnetic forces within a nebula, you WILL see higher gas densities along the magnetic lines of force -- the same idea as when you have iron filings on a sheet of paper and put a magnet under it: those filings will align with the field lines of the magnet.
This could be an interesting topic (the whole tread). I hope some good answers come out of it!
(IANA astromoner, just a physicist)
You have to consider where they got the angular momentum to begin with:
A solar system isn't a bunch of objects that happen to be in the same place. It was originally a gas cloud (perhaps a nebula), which had a little bit of rotation (from whatever source: nova, magnetic fields, or the like). The gas particles, while very dilute from our standards, still interact enough to equalize their (average) velocities. As it collapses, conservation of angular momentum makes it spin faster, until it's dense enough for objects (asteroids, planets, sun) to condense. And since they all condensed out of that same cloud, they're all approximately aligned to the same orbital plane that the original cloud had. (The same explanation applies to why the axes of rotation are also mostly aligned.)