Earth's Origin and Composition - Theories of the Universe
UNIT 1: EARTH'S ORIGIN AND COMPOSITION
CHAPTER 1: ORIGIN AND STRUCTURE OF THE EARTH
Theories on the Origin of the Universe
Universe is everything that exists.
The Big Bang happened about 13.8 billion years ago.
The Big Bang took place everywhere.
Our sun is a star.
The term Big Bang refers to the origin of our universe.
Cosmology: The study of the origin, properties, processes, and evolution of the universe.
Astronomy: Branch of science that deals with celestial objects and space.
Learning target:
Describe the historical development of the theories that explain the origin of the universe
Compare the different hypotheses explaining the origin of the solar system
Describe the unique characteristics of Earth necessary to support life
Explain that Earth consists of four subsystems across whose boundaries matter and energy flow
Theories
Many scientists tested ideas through experiments and observation.
They followed the evidence wherever it leads, and they questioned everything.
Genesis
The narrative form Genesis, described how God separated light from darkness, created the sky, land, sea, moon, stars, and every living creature in a span of six days.
Cyclical or Oscillating Universe
Hindu Rigveda - cyclical or oscillating universe in which a “cosmic egg” or Brahmanda containing the whole universe.
Primordial Universe
Anaxagoras original state of the cosmos was a primordial mixture of all its ingredients, which existed, in infinitely small fragments of themselves.
Atomic Universe
Leucippus and Democritus the universe was composed of very small, indivisible and indestructible building blocks known as atoms.
Aristotelian Universe
Geocentric universe Earth is at center surrounded by concentric spheres of planets and stars and the four classical elements which were acted by two forces – gravity and levity.
Geocentric Universe
The Universe with the Earth at the center, surrounded by the Moon, Mercury, Venus, Sun, Mars, Jupiter, Saturn, and the Sphere of fixed stars.
Heliocentric Universe
Aristarchus of Samos Earth is rotating daily on its axis and revolving annually about the sun in a circular orbit.
Ptolemaic Universe
Claudius Ptolemaeus Planets and the rest of the universe orbit a stationary earth in circular epicycles.
Partially Heliocentric Universe
Nilakantha Somayaji Developed a computational system for a partially heliocentric planetary model, in which the planets orbit the sun, which in turn orbits the Earth.
Copernican Universe
Nicolaus Copernicus Proposed a heliocentric system, that planets orbit around the sun
Stimulated further scientific investigations and became a landmark in the history of modern science (Copernican revolution)
Copernican Universe
Thomas Digges (English Astronomer) - Existence of multitude of stars extending to infinity
Copernican Universe
Giordano Bruno (Italian Philosopher) - the solar system is not the center of the universe, rather a relatively insignificant star system among infinite multitude of others.
Copernican Universe
Johannes Kepler - abandoned the classical assumption of circular orbits in favor of elliptical orbits
Johannes Kepler's Elliptical orbit
Planets including Saturn, Jupiter, Mars, Earth, Venus and Mercury orbiting the sun in elliptical orbits.
Static or Newtonian Universe
Isaac Newton Published Principia A static steady state, infinite universe
Matter on the large scale in uniformly distributed and the universe is gravitationally balanced but essentially unstable
Cartesian Vortex Universe
Rene Descartes (French Philosopher) Outlined a model of universe with many of the characteristics of Newton’s Static, infinite universe. The vacuum of space was not empty at all but filled with matter that swirled around in large and small vortices
Einsteinian Universe
In his theory of gravity, it was not dissimilar to Newton’s in that the universe was static, dynamically stable, which was neither expanding nor contracting
Einsteinian Universe
He added a cosmological constant to his general theory of relativity equations to counteract the dynamical effects of gravity, which would have caused the universe to collapse.
Hubble’s discovery
By studying the light emitted from various galaxies, Hubble discovered that the light appeared displaced toward the red end of the spectrum.
It became apparent that our universe was ceaselessly expanding outward, and all galaxies housed within it were moving away from one another.
Big Bang Model of the Universe
The current accepted model on the formation of the universe
Big Bang Model of the Universe
Universe as originating in an infinitely tiny, infinitely dense point or singularity between 13 to 14 billions years ago
Big Bang Model of the Universe
Matter was not present at the beginning of time; there was only pure energy compressed in a single point called singularity
Oscillating universe
The oscillating universe followed the general theory of relativity equations of the universe with positive curvature
Result in the universe expanding for a time and then contracting due to the pull of its gravity in a perpetual cycle of big bang and big crunch
Steady state Universe
Proposed by the English astronomer Fred Hoyle and the Austrians Thomas Gold and Herman Bondi.
Universe expanded but did not change its density
Inflationary Universe
American Physicist Alan Guth
Incorporated a short, early period of exponential cosmic inflation to solve the uncertainties of the standard big bang model
Multiverse
Andrei Linde developed a theory explaining that the universe is just one of many bubbles in the multiverse
4 Popular theories on the Origin of the Universe
Big Bang Theory
Expanding Universe Theory
Inflationary Big Bang Theory
Steady State Theory
Big Bang Theory
Universe began from a single primordial atom, a tiny, compact point where all the matter and energy in the known cosmos were crammed
Expanding Universe Theory
Since the Big Bang Explosion, the universe has been expanding and the galaxies are moving away from each other
Inflationary Big Bang Theory
Universe underwent a phase of extraordinary expansion
Steady State Theory
There is neither beginning nor end of the universe.
Universe is homogenous, isotropic, and constant in time.
Components of the Universe
Stars
Galaxies
Nebula
Planets
Space telescopes
Stars
Giant, hot ball of gas held together by gravity
Powered by the fusion of hydrogen under conditions of extreme temperature, mass, and density, it generates light and heat
Galaxies
Collection of stars, dust, and gases bound together by gravity
Classification of Galaxies
Spiral Galaxy
Consist of central, dense area surrounded by spiraling arms.
Barred Galaxy
Has a bar-shaped structure in the center
Elliptical Galaxy
Looks like the central portion of a spiral galaxy without the arms
Lenticular Galaxy
Lens-shaped, with a smooth, even distributed of stars. No Central dense area
Irregular Galaxy
Peculiar shape, does not appear to rotate like other galaxies
Nebula
An interstellar cloud of gas and dust
Other nebulae are regions where new stars are beginning to form, hence it is called “star nurseries”
Planets
Any of the primary bodies that orbit the sun or another star
Space telescopes
Hubble Space Telescope
Collect electromagnetic radiation from objects in space
Voyager I and II
Investigated Jupiter, Saturn, Uranus, and Neptune
Galileo Spacecraft
Was in orbit around Jupiter from 1995 to 2003
Gathered information about Jupiter’s atmosphere and its storm systems
Cassini-Huygens
Launched in 1997 to study and orbit around Saturn
Chandra X-ray Observatory
A telescope specially designed to detect X-ray emission from a very hot regions of the Universe
Compton Gamma Ray Observatory
A space observatory detecting photons. A sophisticated satellite observatory for observing the high-energy universe
Spitzer Space Telescope
Launched in 2001 to detect infrared radiation
James Webb Space Telescope
Launched in 2011 to detect infrared radiation from objects in space