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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."
> A couple in the Hamptons has asked the same group of scientists to determine why socks dissapear in the dryer.
They disappear into the electronic equivalent of a black hole, and re-appear on the internet as sock puppets.
Sheesh, evil *and* a jerk. -- Jade
I'm confused. The title suggests they've solved the mystery, but didn't they just find a huge clue? I mean, I can't come upon a murder, find a footprint, and say I finished. There's much more to it than that. Yes, this is a huge step, but no, everything isn't "solved." In fact, they could be completely wrong...
Whatever would iron have to do with this? This is about plasma movement in a magnetic field. Or did you think star explosions ejected nice, neutral iron atoms? Here's a clue: the magnetic moment of iron is caused by its outer electrons.
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!
On a solar system scale, the spin of the central body plays a large role in this, but it is still a kind of a game of chase-the-tail.
When the whole system is still gas, something starts it spinning -- a simple thing like a star passing nearby gives objects (the gas particles) a bit of angular moment, which is thus transferred to the system as a whole over eons of time through collsions, gravity, magnetic forces, etc.
Now, if a LARGE object passed by in the XY plane, and a SMALL object passed by in the YZ plane, you will end up with a spin *mostly* in the XY plane, but the *WHOLE SYSTEM* will balance out with a single plane of spin somewhere in between.
Eventually the smaller objects become larger objects, which collide less, thus distributing the angular moment less efficiently. There may be one central body spinning in the XY plane, but a few of the large objects can have a wildly different orbital plane. But not many objects will HAVE this wildly different orbital plane, because back when the system was being formed, the angular moment transfer WAS very efficient.
Also, 'circular' orbits, like the earths or mars or Jupiters, are fairly rare on a random scale of things; and if you have a bunch of objects orbiting in different planes with highly ellipical orbits, they have a much higher chance of smacking into each other (or some larger object, like jupiter) than the same object would if it were in a more circular orbit which happened to be in a different plane than that of the central masses spin. Don't forget the time scales in question here!
Now, finally, in systems like that of the Earth and its huge moon, you get tidal interactions; while the moon will never shift in its orbit enough to be in an equatorial orbit, it *does* shift more closely to one every day, thanks to the 'gravity drag' between itself and Earth. Really what is happening is that the Earths spin is accelerated in the direction of the moons travel (really, this is slowing our spin rate down, think acceleration in the physics sense). Earth has already done this to the moon; hence the 'tidal lock' which has the moon presenting the same side to Earth at all times.
Were you to watch the Earth moon system forever, eventually what you would see is two bodies rotating about a central point, both with the axis of spin of each body being parallel to the axis of rotation about said central point (hope you can visualise that!). In reality this won't occur in any amount of time, the influence of the sun, and the fact that the moon would actually leave earths gravitation influence before alignment could occur prevent it. (The orbit of the moon gets larger as it steals earths rotational momentum).
That was fun.
No, no, no. Mass causes the warping of space which causes gravity, not gravitational "distortions" and the inverse square law still holds just as it does for the Newtonian model; relativistic gravity "looks" the same as Newtonian from any dirction.
As it must, because we can see that gravity does and one expects, in the absence of other forces, for phenomenon such as planetary nebulae to be symetrical.
By the way, you might be interested to know that the density of material in a such a nebula may well be lower than in an earth bound, artificial vacuum chamber. They may look massive from here, but that's because we see the entire mass of the florescing gases from a distance. If we were in the middle of it it might well look like empty space.
Think of a hazy day. You're not in a fog at all and it's only when you try to look across great distances that you realize the air isn't "empty."
KFG
If 80% aren't spherical one must ask why the other 20% are NOT.
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Why even bother to ask why? If you come across something and you can't figure out how it could have occurred, just claim the event or process is the product of Intelligent Design
Why spend year after tedious year engaging in reductionist scientific inquiry when you can just bail out immediately with an answer that cannot be falsified: Intelligent Design
Worried that your invisible sky-ghost or imaginary all-powerful personal friend isn't getting the deferential worship He deserves in this age of secular humanism? Sneak your sky-ghost back into the schools and indoctrinate another generation of devout sheep with Intelligent Design
Remember the "Argument from Personal Incredulity": if you're too thick to figure out how something works, it must be because no one can figure it out! Don't sweat it! Just explain it away by saying it was caused personally God^H^H^H an Intelligent Designer!
Don't waste time asking question or doing science! Just give credit to an Intelligent Designer and go back to sleep!
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