| [00:00:00.01] | ♪Music♪ |
| [00:00:04.05] | ♪Music♪[HD 141569A] [Disks of debris around stars often show striking patterns...] |
| [00:00:08.09] | ♪Music♪[Like arcs] |
| [00:00:12.14] | ♪Music♪[rings] |
| [00:00:16.17] | ♪Music♪[and spirals.] |
| [00:00:20.20] | ♪Music♪ |
| [00:00:23.27] | ♪Music♪[Do these features tell us unseen planets are stirring gas and dust in these disks?] |
| [00:00:27.35] | ♪Music♪ |
| [00:00:31.48] | ♪Music♪[No, according to a new NASA simulation.] |
| [00:00:35.61] | ♪Music♪ |
| [00:00:38.78] | ♪Music♪[Interactions between dust, gas and starlight let disks form these patterns on their own.] |
| [00:00:42.98] | ♪Music♪ |
| [00:00:47.10] | ♪Music♪[Starlight strips electrons from dust.] |
| [00:00:51.22] | ♪Music♪[These electrons heat up nearby gas.] |
| [00:00:55.27] | ♪Music♪ |
| [00:00:59.31] | ♪Music♪ |
| [00:01:02.45] | ♪Music♪[The gas pressure rises, trapping more dust] |
| [00:01:05.60] | ♪Music♪[which then heats more gas, trapping more dust..] |
| [00:01:08.79] | ♪Music♪[and a cycle of growth begins.] |
| [00:01:11.99] | |
| [00:01:14.04] | ♪Music♪[The interplay of dust and gas results in patterns like those seen in real disks.] |
| [00:01:18.09] | |
| [00:01:21.15] | ♪Music♪[Ars, rings and spirals can form by themselves...] |
| [00:01:24.22] | ♪Music♪ |
| [00:01:26.28] | ♪Music♪[no planets needed.] |
| [00:01:29.31] | ♪Music♪ |
| [00:01:32.40] | ♪Music♪ |
| [00:01:35.52] | ♪Music♪ |
| [00:01:38.65] | [Beeping] |
| [00:01:41.70] | [Beeping] |
| [00:01:44.84] | [Beeping] |