ASTR 101 Chapter Notes -Gaia Hypothesis, Ionosphere, Jet Stream
1 Feb 2014
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Venus: venus has great importance as it demonstrated to galileo that venus orbited the sun, due to its phases, thus reinforcing the heliocentric copernican model. Venus can only be viewed with a telescope, however it is covered in a thick cloud layer which prevents observing the planet"s surface. Venus could be used to work out its distance from us and the sun. Transit of venus: when venus passes between earth and the sun, a shadow is cast on the sun, producing a small black spot moving across the sun. Transits are rare as the orbital plane of venus is not the same as earth"s. Halley realized the duration of a transit (how long it takes for venus to travel across the sun) depends on where you were observing it. The difference in duration between two observers allowed for parallax measurements of the distance from earth to venus (provided you knew the distance between the two observers)
