1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Please help: astronomy questions about how earth orbits the sun

  1. Sep 13, 2009 #1
    Below are some questions. I have struggled with these questions so any help would be greatly appreciated. Thank you so much.

    The Earth orbits the Sun:

    a. in a perfect circle

    b.in an ellipse with the sun at the center

    c.in an ellipse with the sun at the focus

    d.in a shape called an epicycle

    e. none of above

    *I know that the earth orbits the sun in an ellipse but would it be b or c? I think the focus but can someone help me?

    During the period of each year when we see Mars undergoing retrograde motion, what is going on? a.Earth is catching up and passing by Mars in our respective orbits

    b.Earth and Mars are on opposite sides of the Sun

    c.Mars is standing still

    d.Earth is standing still

    e. Mars is reversing its direction of orbit around the sun.

    *I have no idea on this. Can someone please explain? My instinct is to say a or b...

    Lastly, One reason to prefer the Copernican model for the solar system over the Ptolemaic one is

    a. Occams razor b.compactification c. chaos d.determinism e.reductionsim

    *I think this is Occams razor because what is simplest is best. Is this what you all think?
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted