If I look into the sky and I see two yellow dots it’s all stars for me. Then I hear one of them is mars and I’m like „ok, still looks the same“. How did the people hundred of years ago discover what’s a close planet and what’s a far away star?
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How they moved in the sky was ‘odd’. Occasionally they would appear to move the ‘wrong’ way.
Both the Earth and the planet are orbiting the Sun. So sometimes we would ‘catch up compared to the planet and other times we would appear to ‘fall back. So planets would appear to move one way for part of the year and then appear to move the ‘wrong’ way for other periods
Think of runners on a race track. One on the inside line going quite fast and one on the outside line, plodding along. Sometimes it seems that the direct distance between them is closing, but then other times they are moving apart
The name planets derives from a Greek word planḗtai, meaning wanderers. This was due to this odd looping behavior in the observed sky.
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