Repro ID: venus_4
Title: 4. Earth and Venus lined up in transit formation
Description: However, every 120 years or so a pair of conjunctions occur as Venus crosses the line of nodes and is lined up exactly with the Earth and Sun. At these times, the Sun is directly behind Venus, and we see a transit of Venus across the Sun. If we measure the exact position of the transit across the Sun's disc from many different latitudes, we can use geometry to calculate the size of the Earth's orbit in terms of the size of the Earth.
Creator: Jim O'Donnell
Date: 2004
Credit line: National Maritime Museum
