Remnants of Rock & Ice
Topic/Concept: Remnants of Rock & Ice
Prerequisite knowledge required: The Solar System and its formation should have been covered during the preceding week.
Resources required:
Blackboard and chalk,computer and projector to show images and animations.
Learning Goals:
- Students will learn about properties of comets and asteroids. If the Solar System during the era of planet formation was a construction project on a grandiose scale, then the comets and asteroids are the leftover bricks and mortar.
- Why is a “shooting star” not a star at all? Students will distinguish between asteroids and comets, meteors and meteorites.
- Explore the implications of comet and asteroid impacts for life on Earth, past, present, and future.
Learning Objectives
- Show how a comet has two tails that generally point away from the Sun.
- Discuss the role of comets and asteroids in helping us interpret conditions in the early Solar System.
- Draw diagrams of the Solar System that include the asteroid belt, Kuiper belt, and the orbits of some major comets and asteroids. Include a blow-up of the Inner Solar System showing how a number of known comets have “Earth-crossing” orbits.
- Discuss the origin of meteor showers.
Opening Activity
Movie clips
- Deep Impact. Show the scene where the comet fragment crashes into the Atlantic Ocean, generating enormous tsunamis that wipe out New York and much of the Eastern seaboard. This is to get the students’ attention.
- SOHO/NEAT and SOHO/Maccholz Comet clips. These are animations made from time series of SOHO/LASCO images showing spectacular comets passing near the Sun. The tails of these comets can be seen to swing about as the comet passes thru its perihelion point.
Concept Activity/Task: Divide students into groups of 3. Hand out data sheets giving the sizes of the orbits of all of the nine (now, 8+Pluto et al.) planets. Also include orbital parameters of half a dozen major comets (Encke, Halley, etc.) and asteroids (Ceres, Icarus, etc.) but leave a few bits of information blank on these – give the period and eccentricity only and ask students to calculate the semimajor axis of an elongated cometary orbit, for example. Ask students to draw diagrams of the Solar System using this information. The diagrams do not (indeed cannot) need to be to scale but the relative distances of comet aphelions and outer planet orbits must look right.
Have representatives of these groups come to the board and reproduce their diagrams, some showing the entire Solar System some for inner Solar System only. Discuss these with the entire class. Ask students to fill in the approximate path of the tail material from Comet Encke. Note that this path crosses Earth.
Then draw an example “side-view” or the solar system. Guess what? It’s 3-D! Comets don’t always stay in the plane of the planets! Ask students to interpret this in light of what they know about Solar System formation and dynamics.
Assignment
We will schedule 2 or 3 evening screenings of the movie Armageddon. This film is a terrible representation of the science of asteroids and meteor showers and lots of other things! But it sure was popular. In attending these screenings, which will be optional but count toward extra credit, students will take notes on the scientific inaccuracies they observe in the movie (and accuracies, if they can find them!). These lists will be handed in, and prizes will be given out at a later date in lecture for the greatest number of valid science snafus spotted, the most insightful observations, etc. Purpose of this is to have a little fun but also to develop students’ ability to critique representations of science in the popular media.