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The Big Bang project (astronomy) (3)
- 1. The Big Bang BY:ASHLEY JAMES AND TAYLOR MAULDIN
- 2. What is theBig Bang? The Big Bang Theory is a theory in astronomy that the universe originated billions of years ago in an explosion from a single point of nearly infinite energy density. This is the leading hypothesis of how the Universe first started. According to the standard theory, the Universe began its existence as “singularity” around 13.7 billion years ago
- 3. Evidence for theTheory There is evidence that galaxies appear to be moving away from us at a certain speed proportional to their distance. This is known as “Hubble’s Law”, named after Edwin Hubble who discovered this law in the 1900’s. Scientists discovered the leftover radiation from the heat of the Earth, thus the Big Bang suggests this is what caused it. The abundance of “light elements” Hydrogen and Helium, found in the observable universe are thought to support the Big Bang Theory. If the universe were eternal, unchanging, and everywhere the same, the entire night sky would be covered with stars. The night sky is dark because we can see back to a time when there were no stars.
- 4. History of theUniverse The history of the Universe started as the universe cooled, and particle production stopped, thus leaving matter instead of antimatter. Fusion turned remaining neutrons into helium within the first three minutes. Radiation traveled freely after formation of the atoms (no more electrons scattering); age = 380,000 years. A Belgium priest named Georges Lemaitre was the first to suggest the Big Bang Theory in the 1920s when he made a theory that the Universe began from a single primordial atom. The early universe must have been extremely hot and dense.
- 5. Different Eras Sincethe Big Bang Planck Era: The immediate fractions of a second following the Big Bang, known as the Planck Era, are not well understood. Cosmologists suspect that the four fundamental forces at work in the universe today were combined into a single unified force. Grand Unification Era: This era followed the Planck Era, the era began with gravity’s separation from the other three forces and ended with the separation of the strong force from the electroweak force. Electroweak Era: In the beginning, the strong force decoupled from the electroweak force, releasing a tremendous amount of energy and triggering a sudden rapid expansion known as inflation. The era ended with the separation of electromagnetism from the weak force.
- 6. Different Eras Sincethe Big Bang Elementary Particle Era: known as a “particle soup” filled the universe. Quarks and antiquarks, electrons and positrons, and other particles and antiparticles continually swapped mass for energy via matter-antimatter collisions. As the temperature dropped, the cool temp enabled the strong nuclear force to draw quarks together to form protons and neutrons. Era of Nucleosynthesis: As fusion continued, the protons and neutrons combined into the first atomic nuclei, hydrogen, and some of which fused further into helium and lithium. The coolness in temp dipped too low for fusion to continue, thus the plasma of positively charged nuclei and negatively charged free electrons filled the universe, trapping photons in its midst.
- 7. Different Eras Sincethe Big Bang Era of Atoms: Began as the universe finally cooled and expanded enough for the nuclei to capture free electrons, forming fully-fledged, neutral atoms. Previously trapped photons were finally free to move through space ever since, forming the cosmic microwave background. The universe’s expansion has redshifted the initially energetic photons to microwave wavelengths. The CMB marks the furthest point back in time that we can observe.
- 8. How did theBig Bang happen? Scientists believe that the Universe underwent an extremely brief and dramatic period of inflation, expanding faster than the speed of light. This doubled in size perhaps 100 times or more. This occurred within the span of a few tiny fractions of a second. The cosmic microwave background was the radiation left over from the Big Bang that was detected by Penzias and Wilson in 1965.
- 9. Inflation Within theBig Bang Inflation: Is a process that can make all the structure by stretching tiny quantum ripples to enormous size. Spacetime expands much faster than the speed of light, which is okay because it is NOT matter. These ripples in density then become the seeds for all structures. Inflation of the universe flattens the overall geometry, like the inflation of a balloon, causing overall density of matter plus energy to be very close to critical density, that is the geometry of spacetime is flat.
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- 11. How Does theBig Bang Apply Now? Since its conception, The Big Bang Theory has been constantly challenged. These challenges have led to those who believe in the theory to search for more concrete evidence which then would prove them correct. Many people believe it violates the law of thermodynamics. NASA has recently made some discoveries which lend themselves to the proof of The Big Bang. The Hubble Telescope (named after the father of Big Bang theory) has provided certain clues as to what elements were present following creation.
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