Key Figures and Theories in Astronomy and Cosmology

A collection of flashcards covering the major contributors to astronomical models and the Big Bang Theory, based on lecture notes.

What was Aristotle's major contribution to the model of the universe?

He proposed the Geocentric Model, the belief that Earth is the stationary center of the universe and all celestial bodies revolve around it.

According to Aristotle, what substance are the heavens composed of?

Aristotle argued that the heavens are made of a perfect, unchanging substance called aether.

In what book did Claudius Ptolemy mathematically prove the geocentric model?

He expanded and proved the model in his book Almagest.

How did Claudius Ptolemy explain the retrograde motion of planets?

He created a system of epicycles, or small circular orbits, to explain why planets appeared to move backward in the sky.

What theory did Nicolaus Copernicus propose to challenge the geocentric view?

He proposed the Heliocentric Model, which states that the Sun is the center of the Solar System and the Earth and other planets orbit around it.

Who is known as the Father of the Big Bang Theory?

Georges Lemaître.

What did Georges Lemaître first propose regarding the origin of the universe?

He proposed that the universe began as a single tiny point called a "primeval atom" and has been expanding ever since.

Who coined the term "Big Bang"?

Fred Hoyle, who originally used the term jokingly.

What is the core idea of Fred Hoyle's Steady State Theory?

The idea that the universe has no beginning or end, always looks the same, and continuously creates new matter as it expands.

Which scientist provided the first observational proof of an expanding universe?

Edwin Hubble.

What does Hubble's Law state?

The farther away a galaxy is, the faster it is moving away from us.

What did Arno Penzias and Robert Wilson discover in 1964?

They accidentally discovered the Cosmic Microwave Background (CMB) Radiation.

Why was the discovery of Cosmic Microwave Background (CMB) Radiation significant?

It is the leftover heat from the Big Bang and became the strongest evidence confirming the Big Bang Theory.

What did Stephen Hawking prove mathematically about the origin of the universe?

He proved that the universe began from a singularity, which is an infinitely dense, tiny point.

What is Hawking Radiation?

The theory that black holes emit energy and eventually evaporate.