Mars-Venus

Given that I have Mars-Venus conjunct in my natal chart, I'm always interested in the relative positions of the two planets. At the moment of writing (morning of 27th January 2017), the two planets can be seen close together in the evening sky. Mars is quite faint in comparison to Venus because it over three times further away and has a markedly lower albedo anyway. Here is a depiction of the situation using a screenshot from Stellarium, with annotations added afterwards.

Mars is now in the last degree of Pisces and about to enter Aries. The picture shows the proximity of Mars to the Vernal Equinox, where the Ecliptic and Celestial Equator intersect. As described in my previous post, with screencast added, the two planets will move in tandem through Aries over the next couple of months but will remain a few degrees apart until Venus turns retrograde whereupon the zodiacal distance between the two will increase rapidly.

While Mars is faint at the moment, it isn't always like that. Less than 14 years ago, things were very different as the following paragraph describes:

Figure 1

Mars was closest on August 27, 2003. On Aug. 28, Mars arrived to its "opposition." This is the moment when the Sun, Earth and Mars are in alignment (see Figure 1). Mars grows larger and brighter every time a Mars opposition occurs, about every 26 months (780 Earth days), but this specific event is unique for two additional reasons. The orbits of Mars and Earth are elliptical rather than exact circles—that of Mars even more so than Earth's. At the time of the alignment, Mars was at its closest point to the sun in its orbit (called a Mars perihelion). This phenomena (a Mars perihelic opposition) occurs about every 15 to 17 years. In addition, Earth is quite close to its furthest point from the Sun (call an aphelion), which actually occurs a bit earlier in the year. Thus, Earth is pushing outward toward Mars while Mars is reaching inward toward Earth. This rare coincidence of events brought Earth and Mars extraordinarily close (about 55.8 million kilometres).

That record close distance of 55.8 million kilometres is far closer than Venus is now, at 86 million kilometres. As for the time between the zodiacal conjunctions of Mars and Venus (the synodic period), this can be calculated using the formula: 1/(SPM-SPV) where SPM is the sidereal period of Mars and SPV is the sidereal period of Venus (687 days and 225 days respectively). The result is slightly less than 334 days. However, this is clearly just an average because the actual time between conjunctions can be wildly different.

To illustrate, let's go back to August 29, 2015 when Venus and Mars were conjunct. A relatively short time later, on November 3, 2015, they were conjunct again but they not meet at all in 2016. While the two planets are moving closer together at the current time, they are not conjunct until October 5, 2017. This is a gap of almost two years. However, the gap of 768 days between the first conjunction and the third is 768 days, giving an average of 384 days. There is another conjunction on August 24th 2019. The time between this fourth conjunction and the first is 1456 days, giving an average of 364 days. So the trend seems to be toward the figure of 334 days.

on July 13th 2021, the date of a Mars-Venus conjunction