Exploring the Origins of Planetary Systems with JWST 

Primordial matter was almost all hydrogen and helium. Our solar system was formed from "blown up stars" (only a bit of a simplification) and the matter from the fusion in those stars. Nebula consist of lots of H and less of, but still lots of, other elements. They're formed (roughly) from colliding ejecta from the older stars. So, there will be currents. That is, not necessarily spherical. BUT. Even a spherical distribution of gravitationally bound interacting (colliding) particles with completely random velocities will evolve into a disk. (The symmetry is broken in a statistically random direction (around the center).) Why? Well, think of a crowd. Is it easier (i.e lower energy) for each individual to move randomly, or will it be (lots!) easier for the crowd to settle on a single direction and move together? Similar logic applies to particles (as long as other directions are penalized - like by being more likely to crash into one-another.) BTW, awful introduction in video. I never had a lecturer that stood up in class and read the textbook, but I have had the unfortunate experience of sitting thru presentations in which the speaker just repeated, verbatim, the Power Point slides' text. In the first couple of minutes we learn what? That the September talk doesn't yet have a title? ?? Really? Yeah, definitely critical to put that up front rather than at the end.(/sarc) Anyway, I can't complain too much because I stopped watching at that point. MC didn't even tell us what the current lecture was about!

03:48 News from the Universe - Endless Variety of Planetary Nebulae 08:31 Presenting Nicole Arulanantham 09:56 Tonights talk. 48:40 QnA

I heard that Doug made planetary systems.

All exoplanets give us whetting of our technology to more easily & thoroughly 'see' supposedly livable planets.

Why "Newborn stars are surrounded by disks of gas and dust", not a sphere of dust given the presumed randomness of the primordial matter?

Sorry, everyone, but David won't be joining us. He didn't like the intro.