Many people think that astronomy and astrology are the same thing. There’s actually a pretty big difference – it’s the difference between science and pseudoscience.
It’s easy to mistake astronomy and astrology for the same thing. In fact, until the 17th century, they were one and the same. People studied the movements and positions of stars, planets and other bodies in the sky, and used this information to make predictions about natural disasters, wars, and human fortunes.
Around this time, the scientists Galileo, Kepler, and Newton realised that the Earth isn’t the centre of the Solar System. They came up with a simple, testable idea that explained the motions we observe in the sky. They proposed that the Sun is actually the centre of our Solar System*.
Many great thinkers then realised that their entire model of the Universe was suspect, and they parted ways with the astrology. Astrology remained attached to believing that the positions of celestial bodies have some influence on our lives. The thinkers and scientists who gave up this belief called themselves astronomers. They used observations and testable predictions** to study celestial bodies, and rejected the idea that they have any influence over us.
So should you trust astrology? Carl Sagan refuted this beautifully:
“Astrology can be tested by the lives of twins. There are many real cases like this: one twin is killed in childhood in, say, a riding accident or struck by lightning, while the other one lives to a prosperous old age. Supposed that had happened to me. My twin and I would have been born in exactly the same place and within minutes of each other, exactly the same planets would be rising at our births. If astrology were valid, how would we have such profoundly different fates?”
In a nutshell, astronomy tries to understand celestial bodies using direct observations and physics. Astrology studies the positions of celestial bodies, and uses this to make claims about people’s lives, personalities and future.
*- You can read about how they did this here.