July 29, 2021: Jupiter and Mars are 180° apart along the ecliptic. Dim Mars sets in the west-northwest as Jupiter rises in the east-southeast. This event signals that soon both appear in the sky simultaneously.
by Jeffrey L. Hunt
The Jupiter – Mars opposition occurs this evening. Bright Jupiter, nearing its opposition with the sun next month, rises in the southeast as Mars sets in the west-northwest.
The planets are 180° apart along the plane of the solar system, known as the ecliptic.
This is the fourth planet – planet opposition this month. Venus and Mars are in the western sky while Jupiter and Saturn are in the eastern sky. The first occurred on July 1, when the Saturn – Mars opposition occurred. The Venus – Saturn opposition occurred on July 6, followed by Venus and Jupiter on July 21.
These oppositions occurring in this short span signals that four planets soon appear simultaneously in the sky, in pairs, but in opposite directions.
This is a lead up to the difficult-to-observe appearance of the five bright planets simultaneously on August 18.
From the chart above notice that the portion of the line that extends from Earth to Mars is near the sun. Mars is slowly disappearing into the sun’s glare, making it more challenging to see. It passes behind the sun on October 7 and slowly begins to climb into the morning sky. Additionally, Venus is not far away from Mars, after their conjunction on July 12.
Venus appears in the evening sky with Jupiter and Saturn until it disappears into the sun’s glare and jumps into the morning sky during early 2022.
Articles and Summaries
- Venus as an Evening Star
- Venus Evening Star (Summary)
- Mars during 2021 (Summary)
- July Planet Summary 2021 (Summary)
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.