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♪Music♪[HD 141569A] [Disks of debris around stars often show striking patterns...]
♪Music♪[Like arcs]
♪Music♪[rings]
♪Music♪[and spirals.]
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♪Music♪[Do these features tell us unseen planets are stirring gas and dust in these disks?]
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♪Music♪[No, according to a new NASA simulation.]
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♪Music♪[Interactions between dust, gas and starlight let disks form these patterns on their own.]
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♪Music♪[Starlight strips electrons from dust.]
♪Music♪[These electrons heat up nearby gas.]
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♪Music♪[The gas pressure rises, trapping more dust]
♪Music♪[which then heats more gas, trapping more dust..]
♪Music♪[and a cycle of growth begins.]
♪Music♪[The interplay of dust and gas results in patterns like those seen in real disks.]
♪Music♪[Ars, rings and spirals can form by themselves...]
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♪Music♪[no planets needed.]
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[Beeping]