Astronomy 1021 Lecture Notes - Lecture 28: Interstellar Cloud, Cosmic Dust, Star Formation
19 Jan 2017
School
Department
Course
Professor
Document Summary
Star formation: star formation is a hot research topic and actively pursued here at uwo, spoilers so far: Stars form from the gravitational collapse of an interstellar cloud. Stars start shining when temperature is high enough for nuclear fusion. Dust & gas: the space between the stars seems largely empty at visible wavelengths, however, there is a fair amount of material between the stars; this stuff is called the interstellar medium or ism. The galaxy is dusty: interstellar dust is very small, 1 micrometer in size, more like particles in smoke than the dust we know and love. Nebulae: although interstellar matter is everywhere we look, the interstellar medium is most prominently visible in the nebulae, three different types of nebulae: Dark nebulae: dust absorbs light: often, combination can be seen in single image. A nebular public service announcement: density: density of average nebula. 102 105 particles per cubic centimeter: by my calculation, approx. density of air.
