Theories, Origins, and Structure of the Universe – Vocabulary Deck

A comprehensive vocabulary deck covering key terms, theories, scientists, and concepts related to the origins and structure of the universe.

Geocentric Model

An Earth-centered model of the universe proposed by Claudius Ptolemy.

Claudius Ptolemy

Greco-Roman astronomer who formalized the geocentric model.

Heliocentric Model

A Sun-centered model of the universe proposed by Nicolaus Copernicus and later supported by Galileo.

Nicolaus Copernicus

Polish astronomer who first proposed the heliocentric model.

Galileo Galilei

Italian astronomer whose telescopic observations provided evidence for the heliocentric model.

Johannes Kepler

German astronomer who discovered that planets move in elliptical orbits.

Elliptical Orbits

Oval-shaped planetary paths that replaced the earlier concept of perfect circles.

Isaac Newton

English physicist who formulated the laws of motion and universal gravitation in 1687.

Laws of Motion and Universal Gravitation

Newton’s principles describing predictable mechanical behavior of objects and the force of gravity.

Newtonian/Mechanical Universe

View of the cosmos as a vast machine governed by Newton’s laws.

Steady State Theory

Cosmological model claiming the universe is eternal and unchanging in appearance, with continuous matter creation.

Fred Hoyle

British astronomer; co-author of the Steady State Theory and coiner of the term “Big Bang.”

Thomas Gold

Austrian-born British physicist who co-developed the Steady State Theory.

Hermann Bondi

Austrian-born British mathematician and co-developer of the Steady State Theory.

Big Bang Theory

Prevailing model stating the universe began from a hot, dense singularity about 13.8 billion years ago and has been expanding ever since.

“Primordial Atom” / Cosmic Egg

Early Big Bang concept that the universe originated from a single dense point that exploded and expanded.

Georges Lemaître

Belgian priest-physicist who proposed the “primordial atom” idea, a forerunner of the Big Bang Theory.

Edwin Hubble

American astronomer who discovered galactic redshift, showing the universe is expanding.

Redshift

The stretching of light toward the red end of the spectrum from objects moving away, evidence of cosmic expansion.

Cosmic Microwave Background (CMB)

Faint microwave radiation left over from the Big Bang, discovered in 1965.

Oscillating Universe Theory

Hypothesis that the universe cycles through expansions (Big Bang) and contractions (Big Crunch).

Inflationary Universe Theory

Proposal that the universe underwent an extremely rapid exponential expansion just after the Big Bang.

Alan Guth

American physicist who originated the Inflationary Universe Theory.

Multiverse Theory

Idea that our universe is one of many universes, like bubbles in a cosmic foam.

Dark Matter

Invisible matter that does not emit light but exerts gravitational influence on visible matter.

Absolute Zero

0 Kelvin (−273.15 °C), the theoretical minimum temperature where atomic motion stops.

Radiators

Cosmic objects that emit significant energy, such as stars.

Non-radiators

Objects that emit little or no energy, e.g., dark matter and black holes.

Age of the Solar System

Approximately 4.6 billion years.

Age of the Universe

Approximately 13.8 billion years.

Homogeneous (cosmology)

Property that, on large scales, the universe has the same composition everywhere.

Isotropic (cosmology)

Property that the universe looks the same in all directions.

Biblical Creation Theory

Religious view that God created the universe as described in the Book of Genesis.

Lucy (Australopithecus afarensis)

A 3.2-million-year-old hominid fossil important for understanding human evolution (not directly cosmological).