Lisa Randall: evaluation

Transcript context

…I love it, though. I liked it too. We still don’t know for sure, but what we liked about it… Let me take a step back. We usually assume that dark matter, we being physicists, that it’s just one thing. It’s just basically non-interacting aside from gravity or very weakly interacting matter. Again, we have to get outside this mindset of just humans and ask what else could be there. What we suggested is that there’s a fraction of dark matter, not all the dark matter, but some of the dark matter, maybe it has interactions of its own just the same way in our universe, we have lots of different types of matter. We have nuclei, we have electrons, we have neutrons, we have forces. It’s not a simple model, the standard model, but it does have some basic ingredients, so maybe dark matter also has some interesting structure to it. Maybe there’s some small fraction. The interesting thing is that if some of the dark matter does radiate, and I like to call it dark light because it’s light that we don’t see, but dark matter would see. It could radiate that and then it could perhaps collapse into a disk the same way ordinary matter collapsed into the Milky Way disk. It’s not all the dark matter, it’s a fraction, but it could conceivably be a very thin disk of dark matter, thin, dense disk of dark matter. The question is do these exist? People have done studies now to think about whether they can find them. It’s an interesting target, it’s something you can measure. By measuring the positions and velocities of stars, you can find out what the structure of the Milky Way is, but the fun proposal was that the solar system orbits around the galaxy. As it does so, it goes a little bit up and down kind of horses on a carousel. The suggestion was every time it goes through, you have an enhanced probability that you would dislodge something from the edge of the solar system in something called the Oort Cloud. The idea was that at those times, you’re more likely to have these cataclysmic events such as the amazing one that actually caused the last extinction that we know of for sure. It wasn’t so amazing for the dinosaurs.…

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