Answer:
If we were to study other planets to help us learn about Earth, there are many reasons why, and why not the information may be helpful.
Information from other planets may not be the same a Earth. If we were to study Neptune, and we found that Neptune was -214 degree Celsius on day 45, I would not be the same as on Earth, because maybe on day 45 on Earth, the temperature is 25 degree Celsius. The temperature on Neptune is not the same as Earth, so that piece of information may be unhelpful.
But if we were to see the from October to November, Jupiter and Saturn from Earth looked like they stayed in the same place. From the northern hemisphere, looking south - southwest, you may see Jupiter and Saturn. But in January, Jupiter and Saturn are not in the same place as they were a few months ago. This proves that the planets do move, but some at a slower pace than others.
