Origins of the Universe — Study Notes

Genesis: God separated light from darkness, and created the sky, land, sea, moon, stars and every living creature in a span of six days. $6 \text{ days}$
Rigveda: “cosmic egg” or Brahmanda contains the whole universe expanded out from a single concentrated point called Bindu, which will eventually collapse again.
Nous or Cosmic Mind: Anaxagoras believed the universe began as a chaotic mixture of all things, and a powerful, intelligent force called Nous (Mind) brought order by separating and organizing its ingredients.
Atomic Universe: Democritus and Leucippus held that the universe is composed of very small, indivisible, and indestructible atoms. Also, the universe is one body.
Geocentric VS Heliocentric
- Geocentric: Aristotle and Ptolemy believed that the Earth is in the center of the Universe.
- Heliocentric: Copernicus proposed that the Earth revolved around the Sun.
- Galileo Galilei supported the model but was deemed heretic.
Steady-state, Infinite Universe: In Isaac Newton’s description of the universe, matter on a large scale is heavenly distributed, and the universe is gravitationally balanced but essentially unstable.
Cartesian vortex model of the Universe: Rene Descartes posits that the universe is filled with a fluid medium (ether) that creates vortices, or swirling patterns, to explain the motion of celestial bodies.

Big Bang Theory: describes the universe as expanding, having originated from an infinitely tiny, infinitely dense point around $14 \times 10^{9}$ years ago.
- Georges Lemaitre (Roman Catholic Priest) proposed an early form of the idea.
- Edwin Hubble’s galactic redshift provided observational support.
- Cosmic Microwave Background Radiation (CMBR) discovered by Arnold Penzias and Robert Wilson in $1965$ .
Oscillating Universe: The universe keeps going through a cycle: it expands, then shrinks (contracts), and then expands again—over and over like a big cosmic heartbeat. (Albert Einstein)
Steady State Theory: The universe is always expanding, but it stays the same because new matter is constantly being created to fill in the gaps, so it never changes overall. (Fred Hoyle, Thomas Gold, and Hermann Bondi)
Inflationary Universe: Right after the Big Bang, the universe went through a very fast expansion (faster than light!) in a tiny fraction of a second, stretching space super quickly. (Alan Guth)
Multiverse: this theory sees the universe as just one of many “bubbles” that grew as a part of the multiverse (1983).

Creation narratives vs cosmological models:
- Early myths/tools of explanation (Genesis, Rigveda) offered symbolic frameworks for understanding origins.
- Modern theories rely on observation, testable predictions, and mathematical descriptions.
Geocentric to Heliocentric shift:
- Transition marks a fundamental change in humanity’s view of its place in the cosmos and the methods of science.
Universe as dynamic and evolving:
- From a potentially static or cyclical view to expansion, cycles, or continuous creation, depending on the theory.
Evidence-driven models:
- Hubble’s redshift observations and the CMBR are central observational anchors for the Big Bang and cosmic evolution.
Metaphors and imagery in theories:
- Oscillating Universe described as a cosmic heartbeat to convey cyclic expansion and contraction.
- Cartesian vortices as swirling ether-based motions to explain celestial dynamics.

Historical progression:
- From geocentric models to heliocentric, illustrating empirical testing and theory revision.
- From qualitative mythologies to quantitative, observational cosmology.
Foundational physics references:
- Newtonian gravity implied a universe that is gravitationally balanced but inherently unstable in the steady-state description.
- Descartes’ vortex model represents early attempts to explain motion without invoking action-at-a-distance, using a physical medium (ether).
- Inflationary theory introduces rapid expansion to explain horizon and flatness problems in cosmology.
Core observational pillars cited:
- Galactic redshift as evidence of expansion (Hubble).
- Cosmic Microwave Background Radiation as remnant radiation from a hot, dense early universe (Penzias & Wilson).

Age of the Universe in the Big Bang framework:
- $t \approx 14 \times 10^{9} \ \text{years}$
Description of the Big Bang origin point:
- The universe originated from an infinitely tiny, infinitely dense point: $V \to 0, \ \rho \to \infty.$
Notation and terminology:
- “Brahmanda” as cosmic egg concept (Rigveda).
- “Bindu” as the concentrated point from which expansion begins (Rigveda).

Thematic implications (not explicitly discussed in transcript):
- The shift from mythic explanations to empirical science alters worldview and epistemology.
- The possibility of multiple cosmological models competing or complementing each other based on observational data.
Practical implications for study and examination:
- Be able to identify and explain major historical models and modern theories.
- Know key figures and milestones: Lemaitre, Hubble, Penzias & Wilson, Guth, Einstein, Hoyle, Gold, Bondi, Descartes, Aristotle, Ptolemy, Copernicus, Galileo.

Ancient/early cosmologies: Genesis (six days of creation); Rigveda (Brahmanda/Bindu); Anaxagoras (Nous); Democritus/Leucippus (atomism); Geocentric model (Aristotle, Ptolemy); Copernicus (heliocentrism); Galileo (supporter, later controversial).
Pre-modern physics: Newtonian view of an expansive yet gravitationally balanced universe; Cartesian vortex model with ether.
Modern cosmology: Big Bang (14 x 10^9 years ago; Lemaitre; Hubble redshift; CMBR in 1965); oscillating universe (Einstein); steady state (Hoyle, Gold, Bondi); inflation (Guth); multiverse (1983).

Source: Tomas del Rosario College Balanga City, Bataan; Senior High School; First Semester S.Y. 2025-2026; R.L. BALGOS