Difference Between Astronomy and Astrology

What’s the difference between astronomy and astrology? Astronomy is a natural science that seeks to understand phenomena originated outside the Earth’s atmosphere.

In this sense, it studies celestial bodies (planets, comets, asteroids, stars, nebulae, galaxies, etc.). It involves several scientific branches, such as physics, chemistry and biology to explain spatial phenomena.

Astrology studies the relationship of the stars and their possible influences on human beings and life on Earth.

Despite coming from the Greek for “study of the Stars” (Astro Logus), astrology is a pseudo-science. This means that it is based on scientific facts, but it cannot be proven through the application of scientific methods.

What is astronomy?

Astronomy is one of the oldest sciences in the world and seeks to explain phenomena and objects in the universe. The understanding of heaven has always fascinated human beings, who have already observed the firness in the early days of mankind.

What is astronomy

One of the evidence that we have always been interested in the stars are the various archaeological monuments destined for astronomical observations, such as Stonehenge, in England.

The observations at the beginning of our civilization were methodicic and conferred movements in the sky that were repeated, predicting where a celestial body would be at a certain time of the year and its trajectory in heaven.

Until then, astronomy and astrology were not so distinctive. However, the invention of the telescope began astronomy as we know it today.

Because it is a natural science that seeks to understand the universe, astronomy encompasses several scientific aspects, such as the study of physics, chemistry and the movement of celestial bodies. All this to help in understanding how space has formed and developed in what is currently observed.

Branches of astronomy

Because it needs to understand the most diverse phenomena, astronomy is divided into observational and theoretical astronomy. The same astronomer can make spatial observations and create theories to explain the assisted occurrences.


Observational astronomy consists, as the name says, in observations made by professional or amateur astronomers of phenomena outside the Earth’s atmosphere. These observations are made in a thorough way, analyzing information that reaches Earth through electromagnetic waves or light.

The results of the observations are used by theoretical astronomers, who will study in detail and do deeper analysis of the data, creating theories to explain the phenomena.


The astronomical observations are divided into types, since the professionals study the lengths of electromagnetic waves in different spectra. The following are:

  • Optical Astronomy: The earliest of astronomical approaches, studies the visible light of celestial bodies arriving on Earth.
  • Radioastronomy: Studies electromagnetic wavelengths greater than 1 mm and not based on photons (particle present in visible light).
  • Infrared Astronomy: Method that analyzes the infrared light (wavelengths above the red and not visible to the human eye). It was developed to study cold celestial bodies that do not produce light of their own, such as planets and disks of spatial matter.
  • Ultraviolet Astronomy: More used to study phenomena that emit ultraviolet light, such as blue stars. In this sense, it analyzes characteristics of the thermal radiation emitted by celestial bodies.
  • X-Ray astronomy: Space objects emit X-rays, so this method analyzes these emissions and tries to understand the gases present in celestial bodies.
  • Gamma-Ray astronomy: seeks to analyze and understand objects that emit the smallest magnetic wavelengths. Gamma rays are usually originated by gamma-ray eruptions of objects such as pulares, neutron stars and possible black holes.

The knowledge produced in the field of astronomy over the years has promoted the understanding of gravitational disturbances and the possibility of knowing where a star will be in the sky from simple observations. This led to the creation of subgroups of astronomy.

These subgroups are from studies on the Earth to the ends of the universe. For example, Solar astronomy seeks to understand the sun and its phenomena, since the mother star of the solar system can undergo periods of change, which could affect our planet.

There is also Planetary science, which is a branch of astronomy that studies the planets, those in the Solar system or that were found outside of it, the so-called exoplanets.

Currently, more than 3000 planets have been detected orbiting other stars.

To understand the stars beyond the Sun, we created Stellar astronomy, which studies aspects of the formation and evolution of the stars.

The cluster of stars that form our galaxy, the Milky Way, is studied by Galactic astronomy. This branch seeks to understand the galaxy through data, theories and observations of both the galaxy itself and our neighbours.

Extragalactic Astronomy studies the formation and evolution of galaxies beyond the Milky Way. It is thanks to this subgroup of astronomy that we have passed to better understand the size of the universe, its galaxies and how they organize themselves.

Finally, there is cosmology, which studies the formation and evolution of the universe itself.


Theoretical astronomers use data from astronomical observations to discover the origin of cosmic rays, understand the formation and evolution of specific galaxies and the universe as a whole.

All this respecting natural laws and using widely accepted theories, such as Einstein’s general relativity.

For the elaboration of theories, theoretical astronomers need to resort to information captured from observations. These should cover a wide range of spectra, enabling different points of view.

What is astrology?

For astrology, events on Earth and on a human scale are related to the movements of celestial bodies in the sky.

What is astrology

Nowadays, it is considered a pseudoscience, incompatible with the scientific method. However, until the 15TH century, astronomy and astrology were indistinguishable from one another.

Astrologers believe that the positioning of the planets in the sky at the time of the birth of a person defines not only aspects of his character and personality, but also his destiny.

Although many defend scientific issues in this influence, such as electromagnetic fields, scientists refute these assertions. However, astrology is currently seen by most people as a way to provide insight into the characteristics of the human personality.

With this, astrology as pseudoscience is based on scientific facts (such as the positioning of the planets before the constellations), but cannot be proven by the scientific method.

It is also seen as superstition, because modern physics cannot prove the influence between the positioning of planets and events on Earth. This prevents them from verifying that human issues, in fact, result from such spatial interaction.

How do you understand astrology?

Astrologers divide the sky into 12 sections represented by a circumference. The position of the sun in relation to these points in the sky bounded by constellations at the time of the birth of a person defines his sign.

At the time of birth, each “section” is also divided into 12, in which the “houses” are registered. The houses are also governed by signs. The ascendant sign, which would define aspects of the individual’s personality, is indicated in the first house.

Each house would correspond to some aspect of the individual’s life.

The planets and signs in the houses can change depending on the time the individual was born. For example, someone who was born with the sign of Aries in House 1 could have had Taurus in the same house if he had been born at another time of day.


  • Aries: Individuals born between March 19 and April 21.
    Those born under the sign of Aries would be governed by the planet Mars.
  • Taurus: Individuals born between April 20 and May 20.
    Those born under the sign of Taurus would be governed by the planet Venus.
  • Twins: Individuals born between May 21 and June 21.
    Those born under the sign of Gemini would be governed by the planet Mercury.
  • Cancer: Individuals born between June 22 and July 22.
    Those born under the sign of cancer would be ruled by the moon.
  • Leo: Individuals born between July 23 and August 22.
    Those born under the sign of Leo would be ruled by the sun.
  • Virgo: Individuals born between August 23 and September 22.
    Those born under the sign of Virgo would be governed by the planet Mercury.
  • Libra: Individuals born between September 23rd and October 23rd.
    Those born under the sign of Libra would be governed by the planet Venus.
  • Scorpio: Individuals born between October 24th and November 21st.
    Those born under the sign of Scorpio would be governed by the dwarf planet Pluto.
  • Sagittarius: Individuals born between November 22nd and December 21st.
    Those born under the sign of Sagittarius would be governed by the planet Jupiter.
  • Capricorn: Individuals born between December 22nd and January 19th.
    Those born under the sign of Capricorn would be governed by the planet Saturn.
  • Aquarium: Individuals born between January 20 and February 18.
    Those born under the sign of Aquarius would be governed by the planet Uranus.
  • Fish: individuals born between February 19 and March 20.
    Those born under the sign of Aquarius would be governed by the planet Neptune.

All planetary movements are proven by astronomical observations. Currently, astrologers use observation data from astronomers to elaborate their astrological conclusions. But this is practically the only characteristic in common between astronomy and astrology.

Astronomy vs Astrology

According to current astronomy, even the constellations have changed positions over the course of thousands of years since the emergence of the “study of the Stars”.

In this sense, the International Astronomical Union defined in 1930 that the path traveled by the sun throughout the year (ecliptic) was illuminated by 13 zodiacal constellations (and not 12, as astrology delimits).

The 13 constellations according to Astronomy are: Aries, Taurus, Gemini, cancer, Lion, Virgo, Libra, Scorpio, Serpentarium, Sagittarius, Capricorn, Aquarius and Pisces. Although Serpentarium appears in the records of official constellations that illuminate the ecliptic, this is a group of stars ignored by astrologers.

Moreover, the lack of evidence on such astronomical influence on the personality and events on Earth acts against astrology. Another point always brought to the fore by scientists is the fact that most astrological forecasts are “vague”, and can be applied to various situations of the everyday life of human beings.

However, the view that astrology would be a form of self-knowledge has gained supporters nowadays, when great religions have lost the interest of young people, who seek their own spirituality and understanding of the world.