Iona Physics Warmup

Planetary Orbits

Reference Frame

Consider a solar system with a sun (Black Dot) and two planets (Red and Green dots) . The motions (orbits) may be described from various points of view. A point of view is sometimes called a "Reference Frame" or "Frame of Reference". A heliocentric reference frame has all motion described with the sun considered as stationary at the center. A geocentric reference frame has the particular planet you occupy considered to be stationary at the center, with the sun and all the other planets moving around it.

By pushing the buttons below, view various heliocentric and geocentric orbits, then answer the questions.

PREVIEW

Please type your name:

IN:

You may change your mind as often as you wish. When you are satisfied with your responses, click the SUBMIT button at the bottom of this page.

1. Which is easier to describe?

If you had to describe the orbits in words, or perhaps with a mathematical formula, which (geocentric or heliocentric) do you think would be easier to describe? Explain.

Note: You must use complete sentences.

2. The ancient view.

Which system did ancient people believe to be true? Why? You MUST use complete sentences.

---

3. The current view.

Which system do we use today? Why? Remember to use complete sentences and explain your reasoning.



You may change your mind as often as you wish. When you are satisfied with your responses, click the SUBMIT button.

---

SECTION

Click here to return to the contents page.

Last Update: by Bro. R.W.Harris