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Aaron J. Powner, M.Ed.
High School Science Teacher

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History of the Big Bang Theory

Cumulative Nature of Science

Every discovery leads to more questions or problems

Every great scientist builds new knowledge upon the foundation laid by countless other scientists

Every scientific discovery is either an addition to or a correction of old knowledge

Scientific discoveries need to be published and the knowledge must spread to become generally accepted.

Big Bang Etymology - Important Latin & Greek Words

Sun - Sol in Latin, Helios in Greek

Earth - Terra in Latin, Gaia in Greek

Moon - Luna in Latin, Selene in Greek

Star - Stella in Latin, Astron in Greek

Heaven / Sky - Celestes in Latin, Uranus in Greek

World - from OE woruld or worald having three conotations: (1) "human existence, the affairs of life," (2) "a long period of time," and (3) the "human race, mankind, humanity." Descended from Norse and Germanic words warld, verold, weralt, welt which mean "age of man"

Planet - from Greek planetes (these are often called "spheres") meaning "wanderers" which refers to wandering stars that don't follow the normal motions of the constellations (retrograde motions)

Cosmos - from Greek kosmos which means "orderly arrangement" but evolved to mean "the world of mankind" and then to mean "the universe"

Universe - from Latin universum which means "all things, everybody, the whole world"

Evolution - from Latin evolvere "to unroll, roll out, roll forth, unfold" which has evolved to mean "change, growth"

Cosmology - the sciecne of the origin, nature and development of the universe.

Timeline of the Evolution of Cosmology

Most ancient philosophers (Greeks, Egyptions, Babylonians, Chinese, Hindu, etc.) thought of the universe as eternal (unchanging). They also imagined the universe as much smaller than we know it to be today. This timeline focuses on discoveries that led to the modern Big Bang Theory, but neglects many other significant astronomical discoveries.

6th Century BCE - Babylonian Cosmology

The Babylonian world map shows the Earth surrounded by the cosmic ocean, with seven islands arranged around it so as to form a seven-pointed star. Contemporary Biblical cosmology reflects the same view of a flat, circular Earth swimming on water and overarched by the solid vault of the firmament to which are fastened the stars.

4th Century BCE - Aristotelian Cosmology

Aristotle proposes an Earth-centered universe in which the Earth is stationary and the cosmos (or universe) is finite in extent but infinite in time

3rd Century BCE - Heliocentrism Hypothesized

Aristarchus of Samos hypothesized that the Sun is at the center of the known universe with the Earth revolving around it. He identified the "central fire" with the Sun, and he put the other planets in their correct order of distance around the Sun. He suspected that the stars were just other bodies like the Sun, albeit further away from Earth.

2nd Century CE - Ptolemy and Geocentrism

Claudius Ptolemy summarized observations of ancient astronomers for the previous 800 years and then proposed his own model of the universe in his book entitled 'Almagest'. At this point in history, the solar system was thought of as being the entire universe, which has a fixed size. Ptolemy envisioned the universe as a set of nested spheres in which the moon, sun, and planets, and stars revolved around a stationary Earth at its center. According to Ptolemy's calculations, the distance from Earth to the sphere of the stars (celestial sphere) is about 20,000 times the Earth's radius.

8th Century CE - Hindu Cosmology

Puranic Hindu cosmology proposes that the Universe goes through repeated cycles of creation, destruction and rebirth, with each cycle lasting 4.32 billion years.

964 - Distant Galaxies Observed but Not Understood

Abd al-Rahman al-Sufi (Azophi), a Persian astronomer, makes the first recorded observations of the Andromeda Galaxy and the Large Magellanic Cloud the first galaxies other than the Milky Way to be observed from Earth, in his Book of Fixed Stars

13th Century - Earth Rotates on Axis

Nasīr al-Dīn al-Tūsī provides the first empirical evidence for the Earth's rotation on its axis

16th Century - Tyconic System

Tycho Brahe proposes a universe in which the planets orbit the Sun and the Sun orbits the Earth

1543 - Heliocentrism

Nocolaus Copernicus hypothesized that the Sun is the center of planetary motion (including Earth) in his book 'On the revolution of heavenly spheres'. Copernicus still envisioned the solar system as a set of nested spheres that contain the moving celestial bodies. There was little still knowledge about what the Sun, moon, planets, and stars actually are. Heliocentrism is a much simpler model of celestial motions than that of Geocentrism. Visual comparisons | center of motion | motions of planets |

1584 - Infinite Universe

Giordano Bruno accepted heliocentrism, but he rejected the nested spheres view. He proposed that (1) the universe is infinite, (2) the stars are distant suns, (3) each sun/star has its own collection of planets, (4) the solar sytem is a relatively insignificant star system.

1610 - Milky Way Galaxy

Galileo Galilei accepted the hypothesis that the Sun is a star. With his refracting telescope, Galileo realized that the nebular (cloud-like) Milky Way is composed of numerous stars/suns, and proposed that it encompassed the "known universe." Also, in his book, the 'Starry Messenger' he laid out substantial evidence to support the heliocentric model of the solar system.

1609-1621 - Laws of Planetary Motion

Johannes Kepler developed the mathematical laws of planetary motion, based on his works Astronomia nova, Harmonices Mundi, and Epitome of Copernican Astronomy. These laws explain that planents move in eliptical orbits around the sun, rather than perfect circles. They also provide powerful mathematical evidence for the heliocentric model of the solar system.

1687 - Universal Gravitation

Isaac Newton studied Kepler's laws and mathematically derived laws of motion and the theory of universal gravitation. These laws and theories removed the last doubts about the validity of the heliocentric model of the Solar System. Also, Newton's more powerful reflecting telescope allowed much deeper views of the universe than ever before.

1755 - Galaxies outside the Milky Way

Immanuel Kant asserts that the nebulae are really galaxies separate from, independent of, and outside the Milky Way Galaxy; he calls them island universes.

1771 - Messier Objects

Charles Messier, a comet hunter, collected a list of deep-sky objects that irritated him. These Messier objects are not comets, therefore he didn't want to waste time with them. Many of these objects were just swirls of light, like ghostly pinwheels in the night sky. We know now that this object list includes 5 kinds of deep-sky objects: interstellar nebulae, planetary nebulae, open star clusters, globular clusters, and galaxies.

1826 - Olber's Paradox

Heinrich Wilhelm Olbers was the first to clearly describe and publish a logical argument that indicates the universe is finite and evolving (rather than infinite and eternal). This argument had been described by ancient Greek philosophers and and in 1610 by Johannes Kepler. The paradox was not the first to point out this philosophical problem, but he is remembered for clearly explaining it. and contemporaries used the dark night sky to argue for a finite universe. This argument became known as Olber's Paradox. The chief question is, "Why is it dark at night?"

1848 - Primordial Particle

Edgar Allen Poe wrote the essay, Eureka: A Prose Poem, to describe his intuitive suspicion that the universe began as a "Primordial Particle" and evolves through cycles of creative expantion and destructive contraction. He had no scientific reason to propose this, but his imaginative poem inspired several scientists.

1860 - Astronomical Spectroscopy

William Huggins develops astronomical spectroscopy; he shows that the Orion nebula is mostly made of gas, while the Andromeda nebula (later called Andromeda Galaxy) is probably dominated by stars.

1905 - Special Theory of Relativity

Albert Einstein publishes the Special Theory of Relativity, positing that space and time are not separate continua

1915 - General Theory of Relativity

Albert Einstein publishes the General Theory of Relativity, showing that an energy density (matter) warps spacetime - a new explanation of gravity. This theory also mathematically predicted that the universe is either expanding or shrinking (not static). He didn't like the idea of a changing universe, so he added a cosmological constant (a math trick) to stabilize the universe. He later realized this was a mistake.

1922 - Red Shift, Island Universes

Vesto Slipher used spectroscopy and the Doppler Effect (red- or blue-shift in spectral lines) to determine that most spiral nebulae are moving away from Earth at incredible speeds. He speculated/hypothesized that these system might be independent of our Milky Way galaxy. If the Milky Way is our entire universe, then these spiral nebulae might be "island universes" far beyond the boundaries of our own.

1923 - The Universe is Huge!... Bigger than we expected!

Edwin Hubble, using the most powerful telescope of his day, discovered how to calculate the titanic distances between Earth and special pulsing stars called Cepheid variables. His first distance measurement to a flickering star in the Andromeda Spiral Nebula was so huge (around 1 million light years), it had to be too far away to be within our own Milky Way Galaxy. This confirmed that these distant spiral nebulae were other galaxies beyond the limits of our own. The universe is much, much bigger than we ever imagined.

1927 - Universal Expansion Hypothesized

Georges Lemaître, a Belgian Catholic priest proposed an expanding model for the universe to explain the observed redshifts seen in the light from other galaxies around the Milky Way.

1929 - Universal Expansion Confirmed - Hubble's Law

Edwin Hubble combined his distance measurements to other galaxies with large volumes of Red Shift data to calculate the rate at which the Universe is expanding. This theory became Hubble's Law, which further establishes that the Universe is evolving.

1931 - Primeval Atom Hypothesis -- The original name of the Big Bang Theory, proposed by a priest

Georges Lemaître proposed that the universe began with the "explosion" of the "primeval atom" - much as Poe had imagined. He understood that the release of so much energy should have produced a sphere of expanding matter and slowly cooling energies.

1946 - Nucleosynthesis and "Big Bang"

Fred Hoyle led a greoup of researchers in explaining how nuclear fusion of hydrogen and helium in stars produces heavier elements that are released when a star "dies" to be recycled through other stars and planets. In 1948, Hoyle began to publicly reject an evolving universe making fun of Lemaitre's theories by calling them the "Big Bang" as a mockary. He proposed the Steady State theory as an alternative to the Big Bang. Ironically, Hoyle's own work on Nucleosynthesis predicted that most of the material in the universe should be hydrogen and helium if the Big Bang were correct. This was later confirmed, and supported the Big Bang theory.

1964 - Cosmic Microwave Background Radiation (CMBR)

Arno Penzias and Robert Wilson discovered cosmic microwave background (CMB) radiation that matches the George Gamow's pridicted leftover energy from the Big Bang. This is considered the final piece of data that conviced most scienctists that the Big Bang Theory is correct.

1966-1967 - Predictions of Abundance of Light-Weight Elements in Early Universe Confirmed

James Peebles, Robert Wagner, William Fowler, and Fred Hoyle show that the hot Big Bang predicts the correct helium, deuterium and lithium abundances in the universe.

1968 - Strong Anthropic Principle

Brandon Carter proposes the idea that the patterns and forces of nature push cosmic, stellar, and planetary evolution in the direction of forming environments suitible for the evolution of life, including the eventual development of intelligence.

1973-1981 - Relationship between Matter, Gravity, and Large Scale Structure of the Universe

Edward Tryon proposes the idea that the universe might be a large field of quantum mechanical fluctuations (vibrations) where mass is positive wave energy and gravity is the negative potential energy that balances the existence of matter. Viacheslav Mukhanov and Gennady Chibisov realize that these quantum fluctuations could lead to large scale structure in an expanding universe.

1980 - Early Universe Inflation Hypothesized

The horizon and flatness problems state that the universe is too big to have reached its current size in since the Big Bang. Alan Guth explained that early FTL inflation of the Big Bang solve these problems.

1982 - Dark Matter

Owing to the puzzling fact that we cannot find enough matter in space to account for all the gravity that exists, several groups of astrophysicists propose that he universe is dominated by cold dark matter.

1990-1992 - COBE and CMB

Preliminary results from NASA's COBE mission confirms the cosmic microwave background (CMB) radiation and disproves steady state universe theory.

1996 - 1st Hubble Deep Field

The first Hubble Deep Field is released, providing a clear view of very distant galaxies when the universe was around one-third of its present age.

1998 - Age of Universe and Accelerating Expansion Hypothesized

Measurements of distant supernovae by the Supernova Cosmology Project and the High-Z Supernova Search Team indicated that the expansion of the universe is accelerating. This provides evidence for the existence of dark energy and dark matter. This data also refined the estimates of the age of the Universe to roughly 13.7 billion years old.

2006 - Age of Universe Confirmed

NASA's WMAP high definition spacecraft measurements of CMB confirmed that the universe is 13.7 billion years old.

2014 - Location of Earth in our Region of the Universe

Brent Tully lead the team at the University of Hawaii that mapped out all known galaxies (>100,000). The image looks like a "cosmic web." They produced a 3D Map of Laniakea, Galactic Supercluster in which our Milky Way is located

2017 - Gravitational Waves Measured - Accelerating Expansion Confirmed

LIGO and VIRGO projects discovered gravitational waves, confirming Hubble constant value is changing.

2018 - Relativity Confirmed

Gravitational lensing around distant galaxies confirms relativity

Source:

https://en.wikipedia.org/wiki/Timeline_of_cosmological_theories

6th Century BCE - Babylonian Cosmology
	The Babylonian world map shows the Earth surrounded by the cosmic ocean, with seven islands arranged around it so as to form a seven-pointed star. Contemporary Biblical cosmology reflects the same view of a flat, circular Earth swimming on water and overarched by the solid vault of the firmament to which are fastened the stars.
4th Century BCE - Aristotelian Cosmology
	Aristotle proposes an Earth-centered universe in which the Earth is stationary and the cosmos (or universe) is finite in extent but infinite in time
3rd Century BCE - Heliocentrism Hypothesized
	Aristarchus of Samos hypothesized that the Sun is at the center of the known universe with the Earth revolving around it. He identified the "central fire" with the Sun, and he put the other planets in their correct order of distance around the Sun. He suspected that the stars were just other bodies like the Sun, albeit further away from Earth.
2nd Century CE - Ptolemy and Geocentrism
	Claudius Ptolemy summarized observations of ancient astronomers for the previous 800 years and then proposed his own model of the universe in his book entitled 'Almagest'. At this point in history, the solar system was thought of as being the entire universe, which has a fixed size. Ptolemy envisioned the universe as a set of nested spheres in which the moon, sun, and planets, and stars revolved around a stationary Earth at its center. According to Ptolemy's calculations, the distance from Earth to the sphere of the stars (celestial sphere) is about 20,000 times the Earth's radius.
8th Century CE - Hindu Cosmology
	Puranic Hindu cosmology proposes that the Universe goes through repeated cycles of creation, destruction and rebirth, with each cycle lasting 4.32 billion years.
964 - Distant Galaxies Observed but Not Understood
	Abd al-Rahman al-Sufi (Azophi), a Persian astronomer, makes the first recorded observations of the Andromeda Galaxy and the Large Magellanic Cloud the first galaxies other than the Milky Way to be observed from Earth, in his Book of Fixed Stars
13th Century - Earth Rotates on Axis
	Nasīr al-Dīn al-Tūsī provides the first empirical evidence for the Earth's rotation on its axis
16th Century - Tyconic System
	Tycho Brahe proposes a universe in which the planets orbit the Sun and the Sun orbits the Earth
1543 - Heliocentrism
	Nocolaus Copernicus hypothesized that the Sun is the center of planetary motion (including Earth) in his book 'On the revolution of heavenly spheres'. Copernicus still envisioned the solar system as a set of nested spheres that contain the moving celestial bodies. There was little still knowledge about what the Sun, moon, planets, and stars actually are. Heliocentrism is a much simpler model of celestial motions than that of Geocentrism. Visual comparisons \| center of motion \| motions of planets \|
1584 - Infinite Universe
	Giordano Bruno accepted heliocentrism, but he rejected the nested spheres view. He proposed that (1) the universe is infinite, (2) the stars are distant suns, (3) each sun/star has its own collection of planets, (4) the solar sytem is a relatively insignificant star system.
1610 - Milky Way Galaxy
	Galileo Galilei accepted the hypothesis that the Sun is a star. With his refracting telescope, Galileo realized that the nebular (cloud-like) Milky Way is composed of numerous stars/suns, and proposed that it encompassed the "known universe." Also, in his book, the 'Starry Messenger' he laid out substantial evidence to support the heliocentric model of the solar system.
1609-1621 - Laws of Planetary Motion
	Johannes Kepler developed the mathematical laws of planetary motion, based on his works Astronomia nova, Harmonices Mundi, and Epitome of Copernican Astronomy. These laws explain that planents move in eliptical orbits around the sun, rather than perfect circles. They also provide powerful mathematical evidence for the heliocentric model of the solar system.
1687 - Universal Gravitation
	Isaac Newton studied Kepler's laws and mathematically derived laws of motion and the theory of universal gravitation. These laws and theories removed the last doubts about the validity of the heliocentric model of the Solar System. Also, Newton's more powerful reflecting telescope allowed much deeper views of the universe than ever before.
1755 - Galaxies outside the Milky Way
	Immanuel Kant asserts that the nebulae are really galaxies separate from, independent of, and outside the Milky Way Galaxy; he calls them island universes.
1771 - Messier Objects
	Charles Messier, a comet hunter, collected a list of deep-sky objects that irritated him. These Messier objects are not comets, therefore he didn't want to waste time with them. Many of these objects were just swirls of light, like ghostly pinwheels in the night sky. We know now that this object list includes 5 kinds of deep-sky objects: interstellar nebulae, planetary nebulae, open star clusters, globular clusters, and galaxies.
1826 - Olber's Paradox
	Heinrich Wilhelm Olbers was the first to clearly describe and publish a logical argument that indicates the universe is finite and evolving (rather than infinite and eternal). This argument had been described by ancient Greek philosophers and and in 1610 by Johannes Kepler. The paradox was not the first to point out this philosophical problem, but he is remembered for clearly explaining it. and contemporaries used the dark night sky to argue for a finite universe. This argument became known as Olber's Paradox. The chief question is, "Why is it dark at night?"
1848 - Primordial Particle
	Edgar Allen Poe wrote the essay, Eureka: A Prose Poem, to describe his intuitive suspicion that the universe began as a "Primordial Particle" and evolves through cycles of creative expantion and destructive contraction. He had no scientific reason to propose this, but his imaginative poem inspired several scientists.
1860 - Astronomical Spectroscopy
	William Huggins develops astronomical spectroscopy; he shows that the Orion nebula is mostly made of gas, while the Andromeda nebula (later called Andromeda Galaxy) is probably dominated by stars.
1905 - Special Theory of Relativity
	Albert Einstein publishes the Special Theory of Relativity, positing that space and time are not separate continua
1915 - General Theory of Relativity
	Albert Einstein publishes the General Theory of Relativity, showing that an energy density (matter) warps spacetime - a new explanation of gravity. This theory also mathematically predicted that the universe is either expanding or shrinking (not static). He didn't like the idea of a changing universe, so he added a cosmological constant (a math trick) to stabilize the universe. He later realized this was a mistake.
1922 - Red Shift, Island Universes
	Vesto Slipher used spectroscopy and the Doppler Effect (red- or blue-shift in spectral lines) to determine that most spiral nebulae are moving away from Earth at incredible speeds. He speculated/hypothesized that these system might be independent of our Milky Way galaxy. If the Milky Way is our entire universe, then these spiral nebulae might be "island universes" far beyond the boundaries of our own.
1923 - The Universe is Huge!... Bigger than we expected!
	Edwin Hubble, using the most powerful telescope of his day, discovered how to calculate the titanic distances between Earth and special pulsing stars called Cepheid variables. His first distance measurement to a flickering star in the Andromeda Spiral Nebula was so huge (around 1 million light years), it had to be too far away to be within our own Milky Way Galaxy. This confirmed that these distant spiral nebulae were other galaxies beyond the limits of our own. The universe is much, much bigger than we ever imagined.
1927 - Universal Expansion Hypothesized
	Georges Lemaître, a Belgian Catholic priest proposed an expanding model for the universe to explain the observed redshifts seen in the light from other galaxies around the Milky Way.
1929 - Universal Expansion Confirmed - Hubble's Law
	Edwin Hubble combined his distance measurements to other galaxies with large volumes of Red Shift data to calculate the rate at which the Universe is expanding. This theory became Hubble's Law, which further establishes that the Universe is evolving.
1931 - Primeval Atom Hypothesis -- The original name of the Big Bang Theory, proposed by a priest
	Georges Lemaître proposed that the universe began with the "explosion" of the "primeval atom" - much as Poe had imagined. He understood that the release of so much energy should have produced a sphere of expanding matter and slowly cooling energies.
1946 - Nucleosynthesis and "Big Bang"
	Fred Hoyle led a greoup of researchers in explaining how nuclear fusion of hydrogen and helium in stars produces heavier elements that are released when a star "dies" to be recycled through other stars and planets. In 1948, Hoyle began to publicly reject an evolving universe making fun of Lemaitre's theories by calling them the "Big Bang" as a mockary. He proposed the Steady State theory as an alternative to the Big Bang. Ironically, Hoyle's own work on Nucleosynthesis predicted that most of the material in the universe should be hydrogen and helium if the Big Bang were correct. This was later confirmed, and supported the Big Bang theory.
1964 - Cosmic Microwave Background Radiation (CMBR)
	Arno Penzias and Robert Wilson discovered cosmic microwave background (CMB) radiation that matches the George Gamow's pridicted leftover energy from the Big Bang. This is considered the final piece of data that conviced most scienctists that the Big Bang Theory is correct.
1966-1967 - Predictions of Abundance of Light-Weight Elements in Early Universe Confirmed
	James Peebles, Robert Wagner, William Fowler, and Fred Hoyle show that the hot Big Bang predicts the correct helium, deuterium and lithium abundances in the universe.
1968 - Strong Anthropic Principle
	Brandon Carter proposes the idea that the patterns and forces of nature push cosmic, stellar, and planetary evolution in the direction of forming environments suitible for the evolution of life, including the eventual development of intelligence.
1973-1981 - Relationship between Matter, Gravity, and Large Scale Structure of the Universe
	Edward Tryon proposes the idea that the universe might be a large field of quantum mechanical fluctuations (vibrations) where mass is positive wave energy and gravity is the negative potential energy that balances the existence of matter. Viacheslav Mukhanov and Gennady Chibisov realize that these quantum fluctuations could lead to large scale structure in an expanding universe.
1980 - Early Universe Inflation Hypothesized
	The horizon and flatness problems state that the universe is too big to have reached its current size in since the Big Bang. Alan Guth explained that early FTL inflation of the Big Bang solve these problems.
1982 - Dark Matter
	Owing to the puzzling fact that we cannot find enough matter in space to account for all the gravity that exists, several groups of astrophysicists propose that he universe is dominated by cold dark matter.
1990-1992 - COBE and CMB
	Preliminary results from NASA's COBE mission confirms the cosmic microwave background (CMB) radiation and disproves steady state universe theory.
1996 - 1st Hubble Deep Field
	The first Hubble Deep Field is released, providing a clear view of very distant galaxies when the universe was around one-third of its present age.
1998 - Age of Universe and Accelerating Expansion Hypothesized
	Measurements of distant supernovae by the Supernova Cosmology Project and the High-Z Supernova Search Team indicated that the expansion of the universe is accelerating. This provides evidence for the existence of dark energy and dark matter. This data also refined the estimates of the age of the Universe to roughly 13.7 billion years old.
2006 - Age of Universe Confirmed
	NASA's WMAP high definition spacecraft measurements of CMB confirmed that the universe is 13.7 billion years old.
2014 - Location of Earth in our Region of the Universe
	Brent Tully lead the team at the University of Hawaii that mapped out all known galaxies (>100,000). The image looks like a "cosmic web." They produced a 3D Map of Laniakea, Galactic Supercluster in which our Milky Way is located
2017 - Gravitational Waves Measured - Accelerating Expansion Confirmed
	LIGO and VIRGO projects discovered gravitational waves, confirming Hubble constant value is changing.
2018 - Relativity Confirmed
	Gravitational lensing around distant galaxies confirms relativity

Source:	https://en.wikipedia.org/wiki/Timeline_of_cosmological_theories