Synastry, or best known as relationship astrology, comprehends the compatibility of an established relationship, be it professional, familial, romantic, marital, parental, friendships, or enmity. The simplest way to study the compatibility of a relationship is to observe the inter-aspects, if at all formed, between the planets in the horoscopes by placing the planets of one along the wheel of another. The inter-planetary aspects thus formed in the chart majorly impact the said relationship, with each aspect emphasizing the qualities of the planets involved.
Mercury connections and aspects are crucial in synastry since the planet represents the mental outlook and communicative ability in a relationship. Be it easy or challenging aspects, any Mercury inter-aspect is better than none, because communication is the key in every relationship, and no relationship survives without it.
The Mercury-Sun inter-aspects emphasizes on the interaction, communication and the sharing of ideas between the individuals involved in the relationship. Conjunction is the most convenient aspect that Mercury and the Sun form. It becomes easier for the individuals to communicate and connect with each other when Mercury forms a sextile or a trine with the Sun. They imply a positive flow of communication and energy. Whereas a square can bestow disharmony by making the planets sensitive to criticism. A Sun-Mercury opposition can bring lively exchange of ideas but with a difference in opinion. One must have a careful judgment of ideas communicated in the relationship.
A Mercury-Moon contact depends on the emotional stimulus involved in the aspect. An inter-aspect of this combination of celestial bodies integrates the Moon's emotionality with Mercury's intellect. A harmonious conjunction between Mercury and the Moon can lead to deep conversations and implicit comfort in confiding in each other. Mercury influences to initiate and brings the subjects in conversations while the Moon incorporates feelings in them. Lively, insightful conversations are certain to happen in an opposition but these can occasionally go overly intellectual and detached from feelings. A Mercury-Moon square can mostly be critical, unsympathetic, judgmental and insensitive. Other harmonious aspects like the trine and sextile between the Moon and Mercury encourage self-expression, appreciation, sympathy, and understanding.
In a conjunct aspect between the Mercuries of both the individuals in the relationship, the similarities with which they think and speak are certain to be very similar. However, this will depend on the mental temperaments of both the individuals. There is more ease in communicating and interesting conversations will be more frequent when the Mercuries form a sextile. There will be friction and difference in opinion when the aspect formed is challenging, like a square or an opposition. If the aspect formed is a trine, communication and decision making are easy when the individuals share similar ideas and interests.
When one's Mercury forms a challenging aspect, be it a square or an opposition, with the other's Venus, their exchange of ideas and thoughts may eventually act as a source of conflict. These aspects create room for misunderstandings and misinterpretations. Harmonious aspects like the sextile or trine, on the other hand, expands one's artistic horizons and softens temperaments. A Mercury-Venus conjunction can go either way, depending on the other aspects in the synastry chart. It can lead to emotional outbursts from a rather pleasant conversation.
When Mercury forms a square or an opposition with Mars, it can characterize irritation in a relationship which can further provoke fights. The conjunction happens to be the most powerful aspect to occur between Mercury and Mars, as is any conjunction. An easy inter-aspect like a sextile or a trine enables easy flow of energy, and more enthusiastic, lively conversations.
Aspects from Mercury to Jupiter can broaden horizons. There can be frustrations and constant arguments when Mercury and Jupiter forms a difficult aspect like a square, opposition or a quincunx. The individuals may frequently interrupt each other, and find the other's approach to the world as irrational. A harmonious aspect can help build a concrete relationship with great understanding, sympathy and cooperation.
As one's Saturn contacts the other's Mercury, the individuals can discipline reasoning or repress their ability to communicate. The challenging cross aspects between Mercury and Saturn are powerful. It can make the individuals feel emotionally isolated while they try to get over the need to depend on each other and on the relationship. A trine or a sextile between Mercury and Saturn may bring up these feelings too but they are manageable. There is less frustration and more promising of longevity. Moreover, the individuals grow more supportive of each other, and become reliable, understanding, and worthy of trust. Mercury-Saturn conjunction can be a powerful cross aspect which depends entirely on other aspects in the chart.
A Mercury contact with Uranus awakens each other's intellect and saves from boredom. A challenging Mercury-Uranus cross aspect like a square or an opposition has the potential to take the relationship a little off the temperament. There can be mood swings, frequent bouts of emotional outbursts, feeling of isolation, all of it starting ironically from an initial attraction. A harmonious Mercury-Uranus aspect, be it sextile or trine, may share a pleasing environment in the relationship. Conjunction is a powerful aspect in this combination, making it necessary to be careful when handling the relationship.
A Neptune-Mercury contact hints at the possibility and the ability to make up excuses to each other in the relationship, especially when the aspect is a challenging aspect when they individuals go to the extent of lying to each other. Intuitive powers are heightened as Mercury and Neptune form a harmonious trine or a sextile, and the relationship is built on a stable, anchored ground of trust. There is more care and affection, and the heart for appreciation. When the aspect formed is a rather challenging one, like a square or an opposition, the environment can be stressful, indifferent and unwelcoming in the relationship.
Any Mercury-Pluto contact can deepen your understanding of each other that they gradually become tolerant of each other's differences. A hard challenge like a square or an opposition, including a conjunction, tends to bring frequent conflicts of the mind between the individuals in the relationship. A sextile or a trine can help broaden the edges of the mind opening up to new ways of thinking which further creates room for appreciation. The flowing aspects can make the relationship idealistic with patience and harmony.