During 2021 into 2022, Venus passes Mars three times for a triple conjunction. The first occurs on July 12, 2021. The others occur during early 2022, followed by a close approach of the two planets.
by Jeffrey L. Hunt
A triple conjunction occurs when one planet passes another planet three times. Typically, this occurs when planets beyond Earth’s orbit are near opposition, an event when Earth is between the planet and sun.
At this place, the planet outside Earth’s orbit moves eastward, appears to reverse its direction to move westward, and then resumes its eastward motion. This effect is an illusion from our faster moving planet passing a planet farther from the sun.
If another planet is at opposition, then the faster moving planet passes the second planet initially moving eastward, during retrograde, and when the eastward motion restarts.
The faster moving planet is nearer Earth, such as Mars passing Jupiter or Saturn, or Jupiter passing Saturn. This occurs with the classic dimmer planets – Uranus, Neptune, and Pluto – as well, although the Bright Outer Planets – Mars, Jupiter, and Saturn – are easily observed.
Triple conjunctions can occur with bright stars as well. When the star is near the planet’s opposition location, the planet can dance with the distant star.
Venus and Mercury retrograde as well. This occurs when the planets are moving through inferior conjunction, between Earth and the sun.
In this case, Venus or Mercury can pass a more distant planet in the evening sky – as viewed from Earth – as the inner planet moves eastward. The outer planet is approaching its solar conjunction to reappear in the morning sky. The inner planet whips into the morning sky, appearing to overtake the slower, more distant planet for the second conjunction.
After the inner planet’s retrograde ends, it moves past the outer planet for the third conjunction. Certainly, not a “classic” triple conjunction as viewed for planets farther from the sun than Earth.
Other sequences can occur in the Venus – Mars triple conjunction series, such as two conjunctions in the evening sky and one in the morning sky.
Mars seems to wander anywhere along the ecliptic, but Mercury and Venus seem tethered to the sun. Mercury’s greatest separation from the sun can be about 27.5°, while Venus can range up to about 47.5° from the sun.
While Mars can be very bright, this occurs when the planet is near Earth at about the time of oppositions. At Venus – Mars conjunctions, Mars is quite dim.
This effect is best seen in the morning sky after Venus passes between Earth and Sun. The planet races into the predawn sky, appearing higher and incredibly bright. Within a few months of its morning appearance, it stops rising earlier and seems to end its race away from the sun. It reached the limit. This is the region within 47.5° on either side of the sun where Venus can have a conjunction with Mars, Jupiter, Saturn and the other dimmer planets.
The photo above shows a near conjunction in 2017 when Mars was outside the region where conjunctions with Venus can occur.
Triple conjunctions of Venus or Mercury with Mars and the other planets are not unusual. Astronomer Jean Meeus listed conjunctions for these worlds from 2010-2040. During this span Venus passes Mars 29 times. Over 20 of the conjunctions occur during triple conjunction groupings.
The next triple conjunction of Venus and Mars begins with the July 12, 2021, conjunction. Shortly after sunset, Venus is 0.5° to the upper right of the Red Planet. The crescent moon is nearby.
Mars moves into bright evening twilight and reaches its solar conjunction on October 7. The planet slowly moves into the morning sky during the balance of 2021.
Meanwhile, Venus puts on a spectacular display during the final quarter of the year, highlighted by a wonderful grouping with the crescent moon on December 6, 2021.
The planet then seems to dive between Earth and the sun for its inferior conjunction on January 8, 2022. As it retrogrades, it quickly moves into the morning sky.
Near the end of January, Venus stops retrograding with the distance to Mars about 10°. The planet begins to move eastward along the ecliptic, but Mars, moving slightly faster, passes Venus for the second conjunction on Feb 16, but the separation is 6.2°.
Venus picks up speed and passes Mars for the third conjunction on March 6 with a 4.4° separation.
Another event is beginning to occur. Venus celestial latitude is rapidly changing. The planets do not move precisely along the ecliptic. They can stray several degrees above or below the plane referenced by Earth’s orbit around the sun.
During late January, Venus appears 6.8° above the ecliptic. By late March, Venus celestial latitude decreases over 3.8°. During the same period, Mars moves 0.7° farther below the ecliptic. The overall difference is that the planets’ celestial latitude difference is rapidly decreasing, seemingly like a child “smooshing” a sandwich.
The second part of the next event is that Venus is nearing its greatest elongation (46.6°) on March 20.
After the third conjunction, Venus is east of Mars along the ecliptic, but their latitude difference is decreasing. On March 16, the separation reaches 3.9°, but Mars is outside the danger zone. Its solar elongation is 48.2°. The closing of the gap ceases.
On the chart above, notice that Saturn is entering the sky after its solar conjunction. As spring continues, Jupiter moves into the morning sky – four bright planets. When Mercury enters the sky during late spring, a fairly easy view of 5 planets simultaneously occurs.
The next Venus – Mars conjunction occurs on February 22, 2024, followed by a one hidden in bright sunlight on January 7, 2026. The next triple conjunction begins in the evening sky on November 24, 2027.
While this triple conjunction occurs during several months, watching Venus and Mars move close together is an interesting celestial event to anticipate and watch.
December 28, 2021: The Great Andromeda Galaxy is nearly overhead at the end of the evening twilight.
December 29, 2021: The morning crescent moon approaches Scorpius and Mars. In the evening sky, four evening planets – Venus, Mercury, Saturn, and Jupiter – are lined up in the southwest. Venus is rapidly leaving the evening sky.
November 28, 2021: During twilight this evening, the three bright evening planets – Venus, Saturn, and Jupiter – are on parade in the southwestern sky.
December 28, 2021: Brilliant Venus is quickly slipping from the evening sky. Mercury appears beneath Venus after sunset. This duo is joined by Jupiter and Saturn. In the morning, Mars is near Antares and the moon near Spica.
December 27, 2021: The Red Planet Mars passes Antares this morning before sunrise. At the same hour, the moon is near Spica. The three bright planets – Venus, Saturn, and Jupiter – are in the evening sky.