Along with the Signs and Houses of the Zodiac, the Aspects are key to our interpretation of a chart.
Aspects address the angular relationship between planets and points in the Zodiac.
Taking this a step further, if Mercury is at 1 degree Libra in the above horoscope, it will find itself 180 degrees away from Jupiter, or in a direct opposition Aspect to that Planet. Squares and oppositions are also known as hard Aspects. The energy from these Aspects generally represents challenges to be overcome or a balance that needs to be found. Sextiles and trines are considered soft Aspects. Their energy is generally harmonious and beneficial.