Plus the fact that stars twinkle , planets do no
The twinkle or scintillation of light is caused by the atmosphere. Since the light from both the stars and the planets passes through the atmosphere on its way to a detector (whether that is the human eye or a imaging sensor) it stands to reason that both are subject to this effect.
However as astronomer mentions, a star image is a true point source of light (i.e. the star image is smaller or less than the diffraction limit of the telescope) whereas a planetary disk does have a measurable diameter, albeit in arc seconds. That lessens the effect of 'twinkling' on a planetary disc and so to the naked eye the planets appear not to twinkle. If you look at an out of focus planetary image in a telescope you will definitely see the twinkling effect happening.
Concerning the mention of syzygy... in astronomy at least this means an alignment of, such as in conjunction or opposition. The inner planets of Mercury and Venus will experience conjunction when either the planet comes in line with the Sun and the Earth (inferior conjunction) or when the Sun comes between the planet and the Earth (superior conjunction). Mercury and Venus never reach opposition.
The outer planets (Mars outwards) reach opposition when the Earth comes directly in line with the Sun and the planet or conjunction when the Sun comes directly between the planet and the Earth. In the case of the former the planet is visible all night and in the case of the latter the planet passes from the evening sky into the morning sky.
Overall it is a LOT easier to explain the observed planetary events and positions by considering the heliocentric model with the Earth 3rd out from the Sun than it is to take the Earth as a plane with the other planets all orbiting around a Sun which collectively exist above said plane. How can that work?
How this relates to pendulums on Earth exactly I am unsure. So perhaps you could explain.
Stellar parallax definitively proves that the earth is moving around the sun, in relation to the stars, and debunks Brahe’s heliogeocentric model.Stellar parallax definitively proves that the earth is moving around the sun, in relation to the stars, and debunks Brahe’s heliogeocentric model.
Agreed.