Module 2 Activity: Part 2

Geocentric vs. Heliocentric: Looking at Venus from Earth

In Part 2 of Module 2's activity, we'll use some computer `simulators' to see what Venus would look like, as seen from the Earth. We're going to compare and contrast what we would expect to see in both of the major `models' of the solar system: Geocentric and Heliocentric.

Before we start, here's a quick reminder about something in case you need it... You'll be giving your answers in "clock face positions", like "3 o'clock" or "9 o'clock". If you mostly use a digital watch or phone to check the time, these "o'clocks" might be unfamiliar to you. Here's a picture of a clock face in case you need a reminder. Also, the terms "clockwise" and "counterclockwise" will probably come up later in the quarter, so here's a reminder of those terms, too:

Let's imagine you lived in the Europe of the early 1600s, when Galileo made the first observations of Venus with a telescope. With the unaided eye, Venus only ever looks like a bright, starlike point in the sky. However, with a telescope, it looks big enough to show a disc, and that disc can show phases, like the Earth's Moon.

The questions here in Part 2 of the Module 2 Activity use two computer simulations. They show where the Earth, Sun, and Venus are in each model, and they show what Venus would look like through a telescope. The actual simulations are at the end of these instructions, in case you want to try to play with them yourself. However, they were created with Adobe Flash, which is rapidly becoming out of date, and they might not work in your browser.

To get around this problem, I created a video that shows me working with the simulators. You can move the video's time slider back and forth, and it'll be like manipulating the simulators yourself.

Questions 1 through 4 use the Geocentric (a.k.a. Ptolemaic) model, which is the first half of the video (until 3m56s).

Questions 5 through 8 use the Heliocentric (a.k.a. Copernican) model, which is the second half of the video (after 3m56s).

Here's the video:

Once you've answered Questions 5 through 8, go on and answer Questions 9 and 10.

Your scores and feedback comments for this part of the Module 2 Activity will be available January 30th at 10pm.

Here are the Simulators, if you want to play with them:

(Note: These were created at the University of Nebraska, using an old animation format called Adobe Flash. This browser plug-in is rapidly going away, and the animations will probably never get updated, sadly.)

Geocentric Model Simulator:

Heliocentric Model Simulator: