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Galaxy vs. Universe: What's the Difference?

Edited by Aimie Carlson || By Janet White || Published on November 22, 2023
Galaxy is a large system of stars, gas, and dust bound by gravity. Universe is the totality of everything that exists, including all galaxies.

Key Differences

Galaxy is a massive, gravitationally bound system consisting of stars, stellar remnants, interstellar gas, dust, and dark matter. However, universe refers to all of space and time, including all forms of energy, matter, and physical laws governing them.
A galaxy is just one of the billions of galaxies within the observable universe. While, the universe encompasses everything known and unknown, including all matter and energy.
The galaxy we reside in, the Milky Way, is but a tiny part of the universe. Whereas, the universe contains countless galaxies, each with their unique properties and structures.
Galaxies vary in size and shape, including spiral, elliptical, and irregular types. Meanwhile, the universe is the collective expanse that includes these diverse galaxies along with the vast, empty space between them.
The study of galaxies involves understanding star formation, galactic evolution, and dark matter. Exploring the universe entails studying cosmology, the Big Bang theory, and the fate of the cosmos.

Comparison Chart


System of stars and cosmic material
All of space and time, and its contents


Part of the universe
The entirety of everything


Stars, gas, dust, dark matter
Galaxies, energy, matter, laws of physics


Different types (spiral, elliptical)
Encompasses all varieties of galaxies

Study Area

Galactic structure, star formation
Cosmology, origin and fate of everything

Galaxy and Universe Definitions


Cosmic structure.
Galaxies are fundamental structures in the cosmos.


Infinite expanse.
The universe may be infinite in size.


Star system.
Our solar system is part of the Milky Way galaxy.


Cosmic entirety.
The universe is the sum total of space and time.


Gravitational unit.
A galaxy is held together by gravitational forces.


All existence.
The universe encompasses everything we know.


Star host.
Galaxies contain billions of stars.


Physical laws domain.
The laws of physics operate throughout the universe.


Variably sized.
Galaxies range from dwarfs to giants.


Energy and matter container.
The universe contains all energy and matter.


Any of numerous large-scale aggregates of stars, gas, and dust that constitute the universe, containing an average of 100 billion (1011) solar masses and ranging in diameter from 1,500 to 300,000 light-years.


All spacetime, matter, and energy, including the solar system, all stars and galaxies, and the contents of intergalactic space, regarded as a whole.


Often Galaxy The Milky Way.


A hypothetical whole of spacetime, matter, and energy that is purported to exist simultaneously with but to be different from this universe
An alternate universe.


An assembly of brilliant, glamorous, or distinguished persons or things
A galaxy of theatrical performers.


A model or conception of the earth and everything else that exists
“Apart from celestial beings, the aboriginals' universe contained spirits of the land and sea” (Madhusree Mukerjee).


How many galaxies are in the universe?

There are estimated to be billions of galaxies.

How old is the universe?

The universe is approximately 13.8 billion years old.

What is a galaxy made of?

Galaxies consist of stars, gas, dust, and dark matter.

Can we see the entire universe?

No, we can only observe a portion of the universe.

How big is the universe compared to a galaxy?

The universe is immensely larger, containing billions of galaxies.

What's the difference in studying galaxies and the universe?

Galactic studies focus on individual systems, while cosmology studies the universe as a whole.

Is our solar system a galaxy?

No, our solar system is part of the Milky Way galaxy.

What's the role of dark matter in galaxies?

Dark matter significantly influences the structure and dynamics of galaxies.

Is the universe expanding?

Yes, the universe is continuously expanding.

What's the largest galaxy known?

IC 1101 is one of the largest known galaxies.

Can galaxies collide?

Yes, galaxies can and do collide and merge over time.

How do galaxies form?

Galaxies form from the gravitational collapse of matter in the early universe.

Are new galaxies still being formed?

Galaxy formation is an ongoing process in the universe.

What lies beyond the universe?

This remains one of the great mysteries of cosmology.

How do we measure distances in the universe?

Distances are measured using methods like redshift and standard candles.

What's at the edge of the universe?

The concept of an 'edge' doesn't apply to the universe as we understand it.

Can we travel to another galaxy?

With current technology, intergalactic travel is not feasible.

Are all galaxies moving away from each other?

Generally, galaxies are moving apart due to the expansion of the universe.

What is the shape of the universe?

The shape of the universe is still a topic of research, often considered flat.

What's the future of the universe?

Theories suggest it could expand indefinitely, collapse, or stabilize.
About Author
Written by
Janet White
Janet White has been an esteemed writer and blogger for Difference Wiki. Holding a Master's degree in Science and Medical Journalism from the prestigious Boston University, she has consistently demonstrated her expertise and passion for her field. When she's not immersed in her work, Janet relishes her time exercising, delving into a good book, and cherishing moments with friends and family.
Edited by
Aimie Carlson
Aimie Carlson, holding a master's degree in English literature, is a fervent English language enthusiast. She lends her writing talents to Difference Wiki, a prominent website that specializes in comparisons, offering readers insightful analyses that both captivate and inform.

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