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The Big Bang Theory: Origin & Evolution of the Universe Winner of the PowerPoint of the Year Award (2013) Newton’s Static Universe • Universe is static and composed of an infinite number of stars that are scattered randomly throughout an infinite space. • Universe is infinitely old and will exist forever without any major changes. • Time and Space are steady and independent of one another and any objects in existence within them. Newton’s Error • If the universe is as how Newton describes, then why is the sky dark at night? Olber’s Paradox • If space is infinitely old with an infinite number of stars, then in any line of sight in any direction will eventually run into a star. • Using this logic, the sky should be the average brightness of all of these stars. Einstein’s Relativity (1916) • Gravity bends the fabric of space time space and time are influenced by whatever matter (gravity) and radiation are present. Implications of Einstein’s Ideas • Based on the general relativity equations, Einstein predicted the universe must be expanding. • Einstein couldn’t make that theoretical leap and theorized that the universe’s expansion is directly balanced by gravitational contraction, thus yielding a static universe. • Without this idea of a “cosmological constant”, Einstein could’ve been the first to predict that the universe is not static. Edwin Hubble’s Discovery • Hubble observed that the wavelength of light coming from distant galaxies was experiencing redshift . • This means the light source is moving away from the observer and increasing in wavelength (doppler effect). • The longer the light travels, the more it gets redshifted. Hubble’s Law v = H0d v = recessional velocity of the galaxy H0 = Hubble constant D = distance of galaxy to earth • Galaxies are getting farther apart as time progresses, therefore the universe is expanding. – Not only is it expanding… it’s accelerating! • The age of the universe can be derived from Hubble’s constant: For example, if H0 = 73 km/s*Mpc, then T0 ~ 13.7 ± 0.2 byo Origin of the Universe • The universe began about 13.77 billion years ago. • The Big Bang Theory states that, in the beginning, the universe was all in one place. • All of its matter and energy were squished into an infinitely small point, a singularity. • Then…. it exploded. Cosmic Background Radiation • Leftover thermal radiation from the Big Bang. • Uniform; from all directions. • Weak microwaves that are very close in energy to predictions made by the Big Bang Theory. The Nebular Theory • First proposed in 1734 by Emanuel Swedenborg. • In cosmogony, the Nebular Theory is the currently accepted explanation about how a Solar System can form. The Nebular Theory 1. The tremendous amount of material blown out by the big bang starts to group up 2. A large gas cloud (nebula) begins to condense 3. Most of the mass is in the center The Nebular Theory Small chunks grow and collide, eventually becoming large aggregates of gas and solid chunks Protostar The Nebular Theory Pictures from the Hubble Space Telescope show newborn stars emerging from dense, compact pockets of interstellar gas called evaporating gaseous globules The Sun • Huge mass and density rose temperatures in the Sun to one million °C and thermonuclear fusion began. • Fusion - combination of lightweight atomic nuclei into heavier nuclei. H atom + H atom = He atom + energy Birth of the Solar System The Age of the Solar System Earth is ~ 4,570,000,000 years old Meteorites give us access to debris left over from the formation of the solar system We can date meteorites using radioactive isotopes and their decay products The Universe is Highly Organized • We have now discovered many planets orbiting other stars. • The processes that created our solar system have also created an uncountable number of other solar systems. Finally Resulting In…. Possible Fates of the Universe Open Universe: Expands Forever • The universe will continue to expand. All stars will die as the last of their energy is released. Eventually, all matter will be reduced to single atoms moving away from each other. There will be nothing left. Flat Universe: Static • Gravitational attraction between objects will cause the expansion of the universe to slow and, eventually, come to a halt. • Eventually the stars will burn out and it will be a cold, cold place. Closed Universe: Big Crunch • Eventually, all matter and energy will again condense into a single point, possibly no larger than a dime. Another Big Bang will occur and the formation of the universe will begin all over again. • Gravity will then begin to pull everything back to the center of the universe. In any case . . . • Whatever happens to the universe, we are pretty lucky here on earth. • We have the two main requirements for life: – Liquid water – Protection from UV radiation • Perhaps elsewhere in the universe, other planets or moons do, too Research Today • Today, particle accelerators such as the Large Hadron Collider are trying to replicate conditions just after the Big Bang. Remaining Questions • What is dark matter? • What is dark energy? • Can dark energy and matter be detected and studied in labs? • What happened from the birth of the universe, at the instance of the Big Bang, until the end of the inflationary epoch? • What is the ultimate fate of the universe? • What caused the Big Bang?