What are the 17 Branches of Astronomy?

The sky is not only a beautiful sight to behold, but it also has many fascinating things to offer. One of these things is astronomy. Astronomy is the study of celestial objects, such as stars, planets, moons, comets, and nebulae. It is an important science because it helps us understand the universe and how it works. In this article, Astronomy is explained together with its 17 branches.

What are the 17 Branches of Astronomy

The 17 branches of Astronomy are the following:

  • Astrophysics
  • Astrobiology
  • Astrogeology
  • Astrometry
  • Physical cosmology
  • Solar Physics
  • Observational Astronomy
  • Radio Astronomy
  • Optical Astronomy
  • Ultraviolet Astronomy
  • X-ray Astronomy
  • Gamma-ray Astronomy
  • Cosmic Astronomy
  • Planetary Astronomy
  • Solar Astronomy
  • Stellar Astronomy
  • Galactic Astronomy

What is Astronomy?

Astronomy is the science that deals with celestial objects such as stars, planets, comets, and galaxies. Astronomers study the origin, evolution, structure, and behavior of celestial objects. 

They use a variety of techniques to observe the universe, including spectroscopy, photometry, and radar. Astronomy has contributed much to human knowledge in fields such as astrology and planetary science.

Astronomy is the oldest of the natural sciences. It is also considered one of the most difficult and complicated sciences because it deals with many different topics, such as physics, chemistry, geology, and mathematics.

Some of the most famous astronomers include Galileo Galilei, Johannes Kepler, Isaac Newton, and Albert Einstein. These astronomers made major contributions to the fields of astronomy and physics. 

They are all very important to the progress of science and have had a profound impact on our world. For example, Isaac Newton, a British mathematician, and physicist did significant work in the fields of calculus, optics, and gravitation. 

He discovered that the force of gravity is what keeps everything in orbit around the sun. Another example is Johannes Kepler a German mathematician, astronomer, and astrologer. 

He is best known for his three laws of planetary motion, published in 1609, which were the first to describe with mathematical certainty the motion of the planets around the Sun. 

He is also known for his eponymous law of gravitation, which states that the force between two bodies is proportional to the product of their masses and inversely proportional to the square of the distance between them.

Astronomy is a science with many sub-disciplines that study different aspects of astronomy. Below are the 17 branches of astronomy and their definition.


Astrophysics is the study of the physical and chemical properties of celestial objects and their interactions with one another. The word astrophysics literally means “the physics of stars”. 

It also studies astronomical objects that cannot be seen directly, such as gravitational waves and neutrinos. Astrophysics is an essential branch of science that is used to understand how the universe works. 

The field also includes theoretical studies about large-scale structure formation, cosmology, and the origin of cosmic rays. This is achieved by observing the universe at different wavelengths and using physical laws such as physics, chemistry, and mathematics. 


Astrobiology is the study of the origin, distribution, evolution, and future of life in the universe. Astrobiology is not a single scientific discipline, but rather an umbrella term for a broad range of scientific fields that include astronomy, biology, chemistry, geology, physics, and planetary science. 

The term was coined by the NASA astrobiologist Paul Davies. The field includes research on the origin of life on Earth, the search for extraterrestrial life, and the search for evidence of past or present life on Earth. 


Astrogeology is the study of the composition, structure, and formation of the earth and other planetary bodies. It is a branch of astronomy and geology that includes the study of the origin, evolution, distribution, physical properties, and geological history of the universe. 

It is a branch of planetary science and space science that studies the formation and evolution of rocks and minerals in the solar system. The field also includes the study of impact events, craters, and other surface features formed by large objects such as asteroids or comets. 


Astrometry is the science of measuring the positions and movements of stars and other celestial objects. It is an important part of astronomy, which is the study of celestial objects. 

It includes the observation of the positions of celestial objects, and the calculation of the positions of objects based on their observed movements and other observed data. 

The first person to do so was Hipparchus in the 2nd century BC. He was able to calculate the distance between Earth and the Sun, the tilt of Earth’s axis, and the size of the Moon. 

Physical cosmology

Physical cosmology is concerned with the study of cosmological models. It is the study of how galaxies, stars, and the rest of the universe are formed and how they change over time. 

Physical cosmology is a sub-discipline of astronomy that deals with the physical nature of celestial objects, as opposed to their observational properties.

Solar Physics

Solar physics is the study of the sun and its effects on Earth and other planets. The sun is a star that emits solar radiation, which includes visible light, ultraviolet light, infrared light, and x-rays. 

The sun’s heat and light make life possible on Earth. These energies also power the Earth’s weather systems. Solar physicists study how solar radiation interacts with Earth’s atmosphere and what effects this has on climate. 

Observational Astronomy

Observational astronomy is the process of observing astronomical objects in the visible light spectrum with a telescope or binoculars. Astronomers study the universe by looking at the objects in it, whether they are stars, nebulae, galaxies, or planets. 

They also study what is called the circumstellar and interstellar medium, which is the space between stars and planets. Observational astronomy is used to study the stars, galaxies, and other objects that cannot be studied through spectroscopy.

Radio Astronomy

Radio astronomy is the study of celestial objects and phenomena through their radio emissions. Radio waves are electromagnetic radiation that carries energy, and radio astronomy exploits this fact. The word “radio” in radio astronomy refers to the use of radio waves to observe the universe.

Optical Astronomy

Optical astronomy is the use of optical instruments to view astronomical objects. In this field, light from the object is collected by a telescope and projected onto a screen or photographic plate. The image can then be recorded or displayed.

Ultraviolet Astronomy

Ultraviolet Astronomy is the study of objects in the universe that emit ultraviolet radiation. Ultraviolet radiation is invisible to the human eye and can only be detected by specialized instruments. 

Ultraviolet radiation is a form of electromagnetic radiation that has a shorter wavelength than visible light. The sun emits mostly in the ultraviolet range, but other stars and galaxies also emit some ultraviolet radiation.

X-ray Astronomy

X-ray astronomy is the study of objects in space and the universe using X-rays, a form of electromagnetic radiation with wavelengths shorter than those of visible light. X-ray astronomy can be used to study some of the most interesting and important objects in the universe.

Gamma-ray Astronomy

Gamma-ray astronomy is a new field of astronomy that uses the most powerful telescopes and detectors to study the universe in a completely different way. 

It is a field of astronomy that studies the universe using gamma rays. Gamma rays are high-energy radiation that makes up a small portion of the total light from the universe. 

These gamma rays are emitted from the hottest and most energetic objects in the universe, such as black holes, quasars, and active galactic nuclei. 

Gamma-ray astronomy uses a process called spectroscopy to study these objects. Spectroscopy is a technique that allows scientists to observe and identify the chemical composition of distant objects.

Cosmic Astronomy

Cosmic Astronomy is the study of the history and nature of stars, galaxies, and other celestial objects. It is a branch of astronomy that uses telescopes to observe the sky in visible light and in radio waves. Astronomers are interested in the formation and evolution of stars, galaxies, and other astronomical objects.

Planetary Astronomy

Planetary Astronomy is the study of the solar system. It is based on the idea that planets orbit the sun and that objects within the solar system have orbits. 

Planetary Astronomy is a broad field of science that includes studying planets, moons, asteroids, comets, meteors, and other objects in space.

Solar Astronomy

Solar Astronomy is the study of the Sun and other stars in our solar system. It is an area of astronomy that studies the physical properties of the Sun, such as its luminosity, temperature, and mass. 

This can be done through observations, measurements, and calculations. It also includes studying the effects of solar activity on the Earth and other objects in our solar system.

Stellar Astronomy

Stellar astronomy is the study of stars. It is the branch of astronomy that deals with the physical properties of stars and the formation and evolution of stellar systems. It is a very broad field, which includes topics such as star formation, stellar evolution, nucleosynthesis, and stellar death.

Galactic Astronomy

Galactic astronomy is an area of astronomy that is concerned with the structure, content, history, and evolution of galaxies. The study of galaxies is one of the most important ways to understand our own galaxy and its place in the universe.


Astronomy is the science that studies celestial objects and phenomena. It is the study of objects that are outside the Earth’s atmosphere, including other planets, stars, galaxies, and quasars. Astronomy also refers to the scientific method of gathering data about these objects. It is a very broad field of science with many sub-disciplines.

Frequently Asked Questions (FAQs): What are the 17 Branches of Astronomy?

Who is the father of modern astronomy?

Nicholas Copernicus: The Father Of Modern Astronomy 1543-1943.

What is the speed of light?

The speed of light in a vacuum is 299,792,458 meters per second.

What is a telescope?

A telescope is a device that forms an image of distant objects by using lenses or mirrors and is used to see objects that are not physically close.


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17 Branches of Astronomy – Earth How. Retrieved from https://earthhow.com/what-is-astronomy/