The Orbit of star S2 about the Galactic Center
Topic/Concept: Black Holes and Finding Masses using Orbits
Type of Activity: lecture + group work + discussion
Prerequisite knowledge required: newton’s version of kepler’s third law (NVK3), stars
Resources required: worksheet
Learning Objectives: understand that the best way to find masses in the universe is using orbits, become familiar with the evidence for a supermassive black hole at the center of the Galaxy, practice conversions, learn the arc length formula
Common misconceptions: black holes suck
Detailed description of activity: i put the students in groups of three and hand out the worksheet. then we go over the arc length formula on the board and they take notes on the worksheet. then i show them the movie (see associated files below) of S2 orbiting the Galactic center and have them work in groups on the rest of the worksheet. if there is time at the end we discuss their findings as a class.
Assessment: this is mostly done through interacting with the students as they work in groups. you could also collect their worksheets and look them over.
Associated files and images: worksheet (tex), s2orbit.eps (goes with the tex worksheet), worksheet (pdf), s2 orbit video (mpg)
Comments: one thing that i had trouble with is giving a good and quick explanation of a radian.