A telescope pointing towards a star-filled sky Overview of Astronomy and Cosmology

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A telescope pointing towards a star-filled sky


Astronomy and Cosmology are fields of science that study the universe and everything in it. They often intersect with Physics and can be considered as its subfields.

What is Astronomy?

Astronomy is the scientific study of celestial objects and phenomena beyond Earth's atmosphere. This includes studying planets, stars, galaxies, and cosmic radiation.

What is Cosmology?

Cosmology, a subset of astronomy, focuses on the larger structure of the universe and its origins. It often involves theoretical physics and deals with concepts like the Big Bang, dark matter, and the nature of time.

The Big Bang

An illustration of the Big Bang

Observational Astronomy

Observational astronomy involves making measurements of celestial objects and phenomena. Advances in technology have allowed us to observe far-away galaxies and even exoplanets.

Theoretical Astronomy and Astrophysics

Theoretical astronomy and astrophysics involve the use of mathematical models to understand the processes occurring in the universe. This often involves high-level Mathematics and Physics.

Astrophysical Calculations

Equations and graphs representing astrophysical phenomena

Solar System Astronomy

This subfield focuses on celestial objects within our Solar System, such as planets, moons, and asteroids. It has direct implications for space exploration and understanding Earth’s place in the universe.

Galactic and Extragalactic Astronomy

Galactic astronomy studies our Milky Way galaxy, while extragalactic astronomy goes beyond to explore other galaxies and large-scale structures in the universe.


Astrobiology investigates the possibility of life elsewhere in the universe, often intersecting with Biology and Earth Sciences.

Alien Lifeforms

An artist's depiction of an alien planet and lifeforms

Modern and Future Instruments

Instruments like telescopes, satellites, and rovers are essential tools in modern astronomy. Future technologies may even allow us to explore distant planets or capture images of black holes.


Astronomy and Cosmology offer intriguing insights into the universe and our place within it. They raise profound questions about existence, time, and the nature of reality. For more on related subjects, you might be interested in Physics or Earth Sciences. Feel free to return to the Overview of Science or the main Encyclopedia Overview.