Astronomy vs Cosmology [What Is The Difference?]

Astronomy and Cosmology are scientific disciplines that both revolve around the universe. Despite this key similarity, these fields are very different from one another. This will be the subject of this article today.

So, what is the major distinction between Astronomy vs Cosmology? Astronomy is the study of the universe and what resides outside of the Earth’s atmosphere (such as stars, galaxies, nebulae, etc. Astronomers examine the positions, motions, and properties of these celestial objects. Cosmology is actually a subset and branch of astronomy, but it looks specifically at the origin and evolution of the universe. It focuses on key phenomena like the Big Bang all the way through to occurrences today and expectations in the future.

Astronomy vs Cosmology

An easy way to understand the key difference is to view how Astronomers and Cosmologists study their respective disciplines.

Astronomers conduct observations using classical mechanics and optical methods (telescopes, binoculars, and other pieces of astronomical equipment like Spotting Scopes).

They document and classify what they are able to see and use a variety of techniques in order to do so.

Their focus is principally on celestial objects (like stars, galaxies, nebulae, etc) and other celestial occurrences (like star clusters, etc).

Astronomers observe positions, motions, movements, and evolution of objects over time and sometimes spend time researching the chemistry and physics of specific celestial objects.

Alternatively, Cosmologists try to understand and explain the entire evolution of the universe.

They want to help answer the old-age question: how did the universe start and how did it get to where it is today.

Cosmologists also study modern theories, one to note is String Theory.

In recent times, Cosmology has expanded to include the study of other specialist areas like Dark Matter and Dark Energy.

Interestingly, it is through the use of numerical data collected by Astronomers, that Cosmologists infer and can advance their understandings.

What Is Astronomy?

Astronomy is the science of the study of all celestial objects and phenomena in the universe using mathematics, physics, and chemistry.

Planets, Moons, Stars, Nebulae, Galaxies, and Comets are some of the most widely studied.

Phenomena, such as Supernova Explosions, Quasars, Pulsars and Gamma-Ray Bursts are some of the most frequently observed.

For the most part, any object or phenomena that reside outside of the Earth’s own atmosphere will fall under the scope of Astronomy.

Astronomy starts with microscopic focus, observing and classifying single and specific stars, planets and gases.

The science expands to a much larger scale through the study of entire galaxies and star clusters.

Astronomy dates back thousands of years and has been studied for millennia.

Historical findings show that civilizations including the Greeks and Egyptians observed the sky and made empirical documentations of what they saw.

What Is Cosmology?

Cosmology is a specific branch of astronomy looking at the universe in its entirety. The field of study has been shaped by mathematics, observation and analysis.

The word Cosmology comes from the Greek word: ‘cosmologia’ which translates in English to: (orderly arrangement, ornaments) + ‘logos’ (word, reason, plan).

The Universe has been studied throughout history and involves at least three disciplines: physical (science), religion and philosophy.

Disciplines in Each Field of Study

One other to consider is that there are different types of research areas and field of study in both disciplines:

Astronomy has two principle fields:

Observational – centered upon collecting data from observations of astronomical objects. This data is then analyzed through Physics.

Theoretical – uses computer/analytical models to understand and explain objects and phenomena.

Both fields work alongside one another and feed one another directly.

For example, theoretical astronomy uses data to explain results collected from observations. Observations also look to consolidate theoretical findings.

Cosmology has three principle fields:

Physical Cosmology – looks specifically at the physical origins, structures and dynamics of the Universe and its evolution.

Religious or Mythological Cosmology – is centered around explaining the origin, evolution, and eventual fate of the universe from a religious perspective. Religions and the Creation Theory fall into this realm.

Philosophical Cosmology – is a discipline looking from a philosophical perspective; how and why we got to where we are today.

Final Words

As you can see, Astronomy and Cosmology overlap in many ways but there are key distinctions and differences.

To recap; Astronomy is focused principally with the positions, motions, and properties of celestial objects outside the Earth’s Atmosphere.

Cosmology looks at the formation and evolution of the Universe as a whole.