ASTRON 2B03 Lecture Notes - Lecture 9: Sagittarius A*, Methane Clathrate, Low Mass

• School: McMaster University
• Department: Astronomy
• Course: ASTRON 2B03
• Professor: Laura Parker

Document Summary

In each galaxy, there are billions of stars. A(cid:374)d pla(cid:374)ets appea(cid:396) to (cid:271)e fai(cid:396)l(cid:455) (cid:272)o(cid:373)(cid:373)o(cid:374) . But hu(cid:373)a(cid:374) (cid:272)i(cid:448)ilizatio(cid:374) has o(cid:374)l(cid:455) (cid:271)ee(cid:374) a(cid:396)ou(cid:374)d fo(cid:396) a s(cid:373)all sli(cid:272)e of (cid:272)os(cid:373)i(cid:272) histo(cid:396)(cid:455) . Explore the history of our solar system to evaluate whether suitably hospitable planets are uncommon or not around for very long. Solar system starts as a big cloud of gas and dust, slightly more dense than nearby gas and dust. Evolution controlled by competition between forces: gravity pulling in vs pressure pushing out. Conservation of angular momentum means that as gas cools and collapses, it forms disks. First, cooling creates tiny dust-sized solid particles. Rocks collide to form larger and larger proto-planets (or planetoids) Gravity + collisions form planets, which move to clear out the solar system. Planetoids sweep out gaps in the dusty disk. Difference in forces from the disk on either side of planet pulls planets inward. Gravitational interactions can fling planets back out again.