Astrology or Vedic Astrology is an occult science that was revealed by the Holy Sages of India thousands of years ago with a sole aim of making the lives of people better by empowering them with the information about what the planetary bodies are holding up for various aspects of their lives.
In other words- Astrology is a revelatory science that predicts the probable future of an individual as signified by the placement of different planets in his/her kundli or horoscope.
Remember, it is the planets that provide us the results of our past karmas in this current lifetime. If the set of karmas that a particular planet is holding to unfold for an individual is good then the planet gives that individual good results in that particular aspect of his/her life that the planet is associated with as per its placement in the natal horoscope of that individual.
However, if the planet is holding up bad karmas of an individual then the planetary results are detrimental with respect to the aspect of life that the particular planet is associated with.