# Geocentric vs heliocentric model evidence

1. Feb 12, 2016

### Puchinita5

1. The problem statement, all variables and given/known data
I wasn't sure where the most appropriate place to post this question is. But anyway.

Which of these, if any, can be used as evidence that the Earth revolves around the sun.
1. The phases of the moon
2. The seasons
3. analemma of the sun
4. solar and lunar eclipses
5. the sun is more massive than the Earth
6. because we have observed it from space with probes

I know there is other evidence, but I'm trying to see if any of these also make sense and I should add them to the list. I think 1-4 can be explained using the geocentric model too. Laws of gravitation I guess would make 5 an okay answer. I'm not sure if we really have "observed" the Earth going around the Sun.

Thoughts?

2. Relevant equations

3. The attempt at a solution

2. Feb 12, 2016

### Staff: Mentor

5 plus gravity is a very strong argument.
Every space probe far away from Earth has to take the current position of Earth into account to communicate with Earth. And that position is correct in one model only.
Of course we have.

3. Feb 14, 2016

### Puchinita5

okay cool, I guess I was taking the word "observe" too seriously.... The first 4 can be explained somehow in a geocentric model right? I figure it must because these were all things observed back then and they seemed content with the geocentric model despite these observations. The analemma one is really confusing me, I just can't visualize in my head if you could get an analemma in a geocentric system?

4. Feb 14, 2016

### Staff: Mentor

Well, technically you can always choose geocentric coordinates. It just leads to really weird physics once you realize the (other) planets have elliptic orbits around the sun.