Jyotisha (or Jyotish from Sanskrit jyotiṣa, from jyótis- "light, heavenly body") is the traditional Hindu system of astronomy and astrology.
Vedic Astrology is an ancient Indian science which explains planetary motions and positions with respect to time and their effect on humans and other entities on earth. Vedic astrology can be traced thousands of years back. Early Vedic astrology was only based on the movement of planets with respect to stars, but later on it started including zodiac signs as well. According to Vedic astrology ther
e are 27 constellations made up of 12 zodiac signs, 9 planets and 12 houses with each house and planet representing some aspect of human life. Depending on when a person is born, the 12 signs are distributed among the 12 houses and 9 planets are placed in various houses. This visual representation of the snapshot of the signs and planets is called a horoscope chart. Vedic astrology is nothing but interpreting the meaning of these arrangements as it applies to humans and other entities. DIFFERENCE BETWEEEN VEDIC AND WESTERN ASTROLOGY
The most easily referred to difference between the two lies in the method of measurement of the Zodiac. Vedic astrology uses primarily the sidereal zodiac (in which stars are considered to be the fixed background against which the motion of the planets is measured), whereas most Western astrology uses the tropical zodiac (the motion of the planets is measured against the position of the Sun on the Spring equinox). This difference becomes only noticeable over time, after the course of several centuries, as a result of the precession of the equinoxes. Synchronically, the two systems are identical, with just a shift of the origin of the ecliptic longitude by about 22 degrees or days, resulting on the placement of planets in the previous sign in Western charts about 80% of the time. SCEINTIFIC BASIS OF VEDIC ASTROLOGY
Ancient Hindu literature is full of mythology related to zodiac signs, constellations (also known as Nakshatras) and planets, which explain a lot of astrological rules. However the popular opinion is that the mythology was just a method that our ancient seers used to explain some very complex physical laws, which were beyond the comprehension of common people. Unfortunately even today's modern science has not been able to fully understand those physical laws behind this ancient method although it's getting there very fast. Our current understanding of the science of astrology lies in statistics and probability. Statistics is the branch of mathematics, which can deal with correlation between two or more seemingly independent events without knowing the cause of that correlation. If in a chart of 1000 people have the same astrological chart then it can be seen that certain astrological rules hold true in 70%-80% of them. In statistical terms we may say that the occurrence of a specific event in one's life when certain planetary combination exists is "statistically significant". Let's say that you flip a coin 1000 times then the probability of "heads" is always near 50%. Now let's say that you observe the results of flipping a coin during the sun set and sun rise. If you find, after an year long test, that probability of "heads " coming up during sunrise is not actually 50%, as expected, but its 70%, then you can actually construct a rule that if you flip a coin during sun rise, the chances of you getting a "heads" will always be more. Vedic astrology can be explained in a similar way. Certain combinations in one's chart actually result in a prediction, which turns out to be correct in 70-80% of the charts having that combination. We may not explain it yet as to why it happens but the evidence is pretty strong that events can be predicted with very reasonable statistical significance.
