― William Shakespeare, Julius Caesar
It gives weight to an object in relation to that which it is being compared. In the UK, people's body weight is measured in 'stones' a concept derived from an older system based upon the weight of an actual stone. In the olden days, it became necessary to standardize physical mass or weight in order to describe size and heaviness to another person. It's something that we've not had to really think about for generations in our current society, but these standardization differences pop up from time to time in science, engineering, and especially while traveling.
Different cultures evolved their own methods of explaining concepts and ideas through relatively understood notions (Pounds vs. Kilograms vs. Stones).
The definition of Gravity hinges upon the understanding of relativity and how things are perceived from another's perspective. (defining a person's weight on the moon, Mars, or under water will be difficult without common perspective).
Gravity then gives meaning to the weight or mass of an object as defined by that object's attraction to a relative body or mass.
Science teaches that the creation of our Universe began with an explosion known as the "Big Bang". Billions upon billions of stars were created from this explosion along with all the planets, moons, and stars within our solar system. We are the resulting life from billions of years of evolution from the cosmic dust scattered throughout the galaxy. Our cellular makeup shares common ancestry with the planets that orbit our sun.
Astronomy is the science of mapping the movement of the planets and stars relative to their orbitals (usually from the perspective of the Earth and Sun). This science has been studied for thousands of years.
Astrology is the science concerned with celestial gravitational attractions and their effects on life. The most commonly studied planetary gravitational mapping is known as the Zodiac Calendar. Many cultures have their own interpretation as to the meanings and observations in what might be regarded as a pseudo scientific study on the planetary effects of the gravitational attractions the planets have upon a developing embryo until birth.
For instance, the Earth's Moon is responsible for the ocean tides. It's gravity, while lesser than the Earths, is significant enough to attract the seas on a molecular level. The Human body is composed of 90% water and our blood is very similar in salinity to seawater. There is enough evidence to argue a correlation between the Moon's gravity and it's effects on humans. (Ask anyone with work experience in an Emergency Room during a full Moon).
If our Moon orbits our planet, which in turn shares an orbital with other planets around a common Sun, then it stands to reason that each planetary body contributes to the gravitational attractions we experience as humans on Earth. On a molecular level we experience gravitational forces that affect our thoughts, actions, and behaviors.
Human's too possess their own 'gravitational pull' to one another. People often find themselves attracted to others who possess qualities that they desire. These high gravity individuals cast an effect on others that can influence and even change normal behaviors. (Observe the effects an attractive woman has on men at the gym).
If the gravitational pull of two objects are equal, then attraction is mutually distributed and balanced. They are equals, free to come and go as they please. An object with more gravitational mass possesses more attraction. This means that lesser gravitational masses will be more attracted and pulled towards the heavier mass. Other gravitational masses can effect the attractions of two separate bodies by introducing a third (or more) gravitational pull similar to the effects of the Sun holding the gravity imbalance of the Earth and Moon in orbit with out them crashing into one another or flying off into outer space. (It reminds me of two parents and a child).
People do not get to choose the circumstances surrounding their birth. A concept that still amazes me today. We have no control over where, when, who, and what we will be born. Our understanding of who we are as a person doesn't form until we are mature enough to process the environment in which we find ourselves. People grow, adapt, and act accordingly to which ever race, religion, wealth, or orientation they are born in to (regardless of the year in which they exist).
Our inherent gravity would determine who we attract and to whom we ourselves are attracted. In this manner, astrology seeks to understand orbital compatibility. Individuals operate on their own orbital frequencies and are best paired with others who share common ground. This is not to say two people should be on the exact same frequency all of the time (that might become tedious), but rather they must orbit one another with enough common frequency in order to build a relationship with respect to each others own orbits. For example, two colleagues getting together for drinks after a tough day at work. They have endured a common labor and wish to relax in a social setting distinctly separate from their daily orbit at work. These individuals can then return to their own lives at home, but share a common perspective together in a single area of their lives. This sharing of perspective is what makes orbital compatibility. In this way, people are defined by the company they choose to keep. The elements of their character are most comfortable in the presence of shared perspectives from common orbits.
We do not get to choose our "Gravity". Seemingly, It chooses us. It's best not to fight with nature, but rather let yourself be guided by its flow. In this way, one doesn't have to force anything and attraction will flow on a molecular level. One can learn to enhance one's "gravitational attraction" by developing their character. By understanding the universal dynamics of nature's forces and building substance to their character, one can feel a sense of their gravitational pull on others. People are naturally attracted to individuals that radiate peace, happiness, and confidence (children can tell it right away). It is an increasingly difficult state of well-being to find with all the distractions of ego in the world. One way this can be achieved is simply by treating others with the same respect that you wish to receive in return and sincerely allowing people to feel good about themselves. When one is in the presence of individuals with this mentality, strong attractions may be felt for them. These individuals may choose to use their high gravitational pull to influence the world around them to better fit their wants, needs, or concerns.
It's a controversial topic with subjective evidence at best. These are my thoughts and feelings with support from pseudo sciences even if there are noticeable patterns to people and zodiac sign memberships. I choose to accept the notion that these signs are general observations and not limitations, and that each of us as humans share a common ancestry to the Cosmic Spark of the Divine.