Astronomy 2022A/B Lecture Notes - Lecture 3: Special Relativity, Schwarzschild Radius, British Home Stores
Document Summary
The geometry of the universe and black holes. Every mass has an effect on the universe (even me!: mass will cause space to curve near it. Closed universe positive curvature, like a sphere. Open universe negative curvature, like a saddle. How to tell flat space from curved space. If (cid:449)e dra(cid:449) a tria(cid:374)gle o(cid:374) a sphere, all the a(cid:374)gles do(cid:374)(cid:859)t add up to (cid:1005)8(cid:1004) deg, all right a(cid:374)gle (90 deg) equals 270 deg. Measuring curvature: draw a triangle on it, get in a spaceship, head straight out, after long distance, make 90 turn and go again, after equal distance, measure the angles for the remaining side. If angles add up to 180 flat, not 180, not flat: unfortunatel(cid:455) (cid:272)a(cid:374)(cid:859)t do this shit (cid:272)a(cid:374)(cid:859)t go far or fast e(cid:374)ough to do this. Is there another way to do this: yes, count the distant galaxies!