Find out what the difference is between astronomy and astrology.

Astronomy and astrology are two concepts that some people use interchangeably. While astronomy and astrology do indeed share a focus on celestial bodies, that is about all they share. A focus.

This post explains the difference between astronomy and astrology, and hence the perhaps more important difference between an astronomer and an astrologist.

Astronomy Is A Science – Astrology Is Not

The main difference between astronomy and astrology is the fact that one is a science and the other is not.

Astronomy is the observation and fact-based description of the universe outside the Earth’s atmosphere. Astronomy tells us how planets move, how black hole accrete mass, how stars shine, how galaxies recede away from us and the answers to many more questions about the universe. It is a science that is based on observations, models and theories, and the results that arise from space models must be reproducible and created using methods that are described within the scientific approach.

Astronomy does not focus on humans. It concerns only the behavior of space phenomenon and events that take place outside Earth. The closest we get to having humans included in astronomy is when we search for life on other planets. And not even in that context can astronomers fully agree when life even means. In other words: humans are insignificant in astronomy.

An astronomer is someone who studies space and the phenomena in it, while trying to answer questions that start with “How…?”.

Astrology differs from this description on all parameters. Astrology is a belief that the orientation of celestial bodies affect our minds and bodies. Astrology in practice is e.g. having a horoscope created for the time and place of birth for a human being, and then believing that the location of planets in the solar system influence the future personality and health of this newborn baby. While the location of e.g. planets of course are scientific, the interpretation of their influence on humans on Earth is highly unscientific and hence the need to call it a belief or superstition.

Astrology has full focus on humans and the use of astrology requires a human to be the subject of reference when interpreting the motion and location of celestial bodies. For this reason, astrology is used by some people to navigate their lives or it works as input when making big decisions.

An astrologist is someone who conveys the astrological interpretation of the location of planets and stars.

Is Astrology Wrong?

Astrology, as such, is not wrong. It’s also not wrong to throw salt over your shoulder after you spill it, or to knock on wood when you hope for something nice to happen. It’s not wrong, but it’s also not science. It’s superstition.

Astrology is a superstitious belief. In a free world, a person can base their life and decisions on whatever they want, as long as they don’t impose harm or threat. It’s not wrong to be superstitious. Even astronomers cross their fingers and knock on wood when they submit grant proposals in the hopes that funding will flow their way this time. But they don’t use it as scientific reasoning, because crossing your fingers in order for something good to happen is just not scientific. It’s fun, but it’s not science.

What is wrong (and I think this is where the debate often centers) is to classify astrology as a science. It’s wrong because it, by definition, is not, but perhaps more importantly it is wrong for ethical reasons. Selling astrology as a science is false advertisement.

Astrology is not a science. And vice versa, astronomy is not a belief.

The two concepts are not comparable, nor interchangeable. One is the scientific study of space, the other is a form of personal life guide. Astronomy can not be used as a life guide, and astrology can not be used in a scientific study about space. Simple as that.

Despite the obvious reasons why astrology is not a science, it is often being sold as one. Most likely because one can earn significantly more money by adding a science label to the fortune-telling. And the arguments in favor relies entirely on the mix-up of causality and correlation.

Let’s take a closer look at what causality and correlation are.

Were You Born On A Rainy Day – Or Does It Rain Because You Were Born?

In astronomy, we need causality to explain a phenomenon. This is how scientists make predictions: They model an event and wait for it to happen in space, somewhere we can observe it. If the outcome of the event matches our model’s prediction, then we have a good idea of how something happened.

A nice example of what causality is is Einstein’s explanation of how Mercury should precess by an extra 43 seconds of arc per century. This would be a consequence of his theory of general relativity, which was formulated some 100 years ago. This behavior of Mercury was already known, but it was yet to be explained what caused this behavior. A cause was missing and Einstein found it in his general relativity theory.

Causality means that “when A happens, then B will also happen” regardless of the number of event repetitions. Causality is a fundamental part of the scientific method.

In contrast to causality we have correlation. Correlation means that two random events happen simultaneously. The best examples of what a correlation is are found on this website. It shows the correlation between random events such as “Number of people who drowned by falling into a pool Vs. Films Nicolas Cage appeared in“. From the graph, these two events correlate perfectly, but of course people don’t drown in pools because there is a new Nicholas Cage film out. From the graph, it looks convincing – but it’s still silly. Correlation is not causality. Correlation can be convincing, but it does not explain anything. It only shows that two random events happen at the same time.

Astrology relies heavily on correlation, and this often gets mistaken as causality. Jupiter rises in the East and you are having financial problems. Add a diagram and it can suddenly seem convincing that the current location of Jupiter has a bad influence on your economic status.

But it doesn’t. If you experience financial problems, it’s probably because of capitalism. Not Jupiter.

Astronomy And Astrology Coexist, But They Are Not Related Today

A few hundred years ago, astronomy and astrology were two ingredients in a soup of science. At the time, it made sense. Scientists were figuring out how stuff was connected and of course it made sense to add ideas of different interactions in the universe, including the proposed interactions between our mind and the celestial bodies.

One can even argue that astrology paved the way for astronomy. In the renaissance, an astronomer could function as personal adviser to the king by providing prognosis for the king’s health and future doings based on stellar constellations and the motion of planets. This gave astronomy a presence in the higher society, which was where acknowledged scientists were found. Even though we later discarded astrology in the scientific community, astronomy is indeed still strongly represented in science.

Today, we have come a long way since the renaissance. We know how tiny atoms and large galaxies work. We know how to fight viruses and heal wounds. We also know that planets don’t affect your fortune in life.

And thankfully, we also know that we, as individuals, are free to believe whatever we want.

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