Tropical timings – the Venus-Earth pentagram

Venus and Earth [credit: space.com]

” data-image-caption=”" data-large-file=”https://tallbloke.wordpress.com/wp-content/uploads/2026/04/venus_earth.jpg?w=614″ src=”https://tallbloke.wordpress.com/wp-content/uploads/2026/04/venus_earth.jpg?w=614″ alt=”" width=”614″ height=”352″ class=”aligncenter size-large wp-image-84522″ srcset=”https://tallbloke.wordpress.com/wp-content/uploads/2026/04/venus_earth.jpg?w=614 614w, https://tallbloke.wordpress.com/wp-content/uploads/2026/04/venus_earth.jpg?w=1228 1228w, https://tallbloke.wordpress.com/wp-content/uploads/2026/04/venus_earth.jpg?w=150 150w, https://tallbloke.wordpress.com/wp-content/uploads/2026/04/venus_earth.jpg?w=300 300w, https://tallbloke.wordpress.com/wp-content/uploads/2026/04/venus_earth.jpg?w=768 768w, https://tallbloke.wordpress.com/wp-content/uploads/2026/04/venus_earth.jpg?w=1024 1024w” sizes=”(max-width: 614px) 100vw, 614px” />
Quoting Wikipedia on Venus:

Orbit in respect to Earth
Earth and Venus have a near orbital resonance of 13:8 (Earth orbits eight times for every 13 orbits of Venus).[161] Therefore, they approach each other and reach inferior conjunction in synodic periods of 584 days, on average.[6] The path that Venus makes in relation to Earth viewed geocentrically draws a pentagram over five synodic periods, shifting every period by 144°. This pentagram of Venus is sometimes referred to as the petals of Venus due to the path’s visual similarity to a flower.[162]
– – –
The five conjunctions (synodic periods) have then moved about 5*144° = 720° = 2*360° = 2 revolutions of the conjunction axis. That’s the background. In reality the degrees of movement total 722.23114°, so each ‘144°’ is in fact slightly more than that, i.e. 144.46228°.

Let’s imagine a theoretical situation then compare it to the reality. Suppose that in 1000 tropical (Earth) years, there are 1625 Venus orbits and therefore 625 conjunctions (1625-1000). If each conjunction is 144° from the last one, total movement is 625*144° = 90000° or 250*360° in 1000 TY. The ratio of Earth:Venus orbit ratio in this scenario (1000:1625) is exactly 8:13 per 5 conjunctions (see Wikipedia quote above), achieved by dividing the numbers by 125.

In reality 996 Earth orbits = 1619 Venus orbits meaning 623 (1619-996) conjunctions. Because the movement is 144.46228° per conjunction, the total movement in 996 TY is unchanged:
144.46228° * 623 = 90000°.

In effect, because of the slight overshoot of the 144°, two conjunctions are ‘lost’ in the period compared to the imaginary, or ideal, scenario. However the total movement of the conjunction axis is still the same i.e. 250*360°. Note that 250 is 2*125, with multiples of 125 being the basis of the ideal scenario.
– – –
Image: Venus and Earth [credit: space.com]
– – –
Related Talkshop posts:
— Jupiter, Earth and Venus’ tropical alignments point to the mean solar cycle length
— The Venus–Earth–Jupiter spin–orbit coupling model.