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Exploring Origins: Universe, Stars, and Galaxies

Delve into the origins of the Universe, stars, and galaxies in Oceanography Chapter 2: learn about the Big Bang theory, cosmic radiation, electromagnetic spectrum, star life cycles, formation of elements, and galaxy types.

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Exploring Origins: Universe, Stars, and Galaxies

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  1. Bell Work 9/8/2011 Chapter 2 in the Oceanography textbook is entitled “Origins”. What might we be studying the “origins” of in this chapter? Oceans Solar System Earth Moon Universe Atmosphere

  2. Origins – Oceanography Chapter 2

  3. Part 1: Origin of Universe & Galaxies

  4. Big Bang Theory • Event that occurred approximately 14 billion years ago. • All mass & energy was concentrated at a geometric point. • The Big Bang marks the beginning of space and time.

  5. Evidence Supporting the Big Bang Theory • Expansion of the universe. • Cosmic Background Radiation. • Nucleosynthesis of light elements. • Formation of galaxies.

  6. ELECTRO-MAGNETIC SPECTRUM Smallest wavelength Largest wavelength What we see with our eyes

  7. Looking at the Crab Nebula with the EM Spectrum X-RAY UV IR RADIO MW VISIBLE

  8. Expansion of Universe 90% of all stars & galaxies observed are moving away from the Milky Way Red Shifted = moving away Blue Shifted = moving towards

  9. Cosmic Background Radiation • Ancient universe had small variations in temperature. • Over 14 billion years, gravity magnified these small differences into clusters of galaxies today. A sky map of cosmic background radiation (microwave) taken by NASA’s satellite called COBE.

  10. Scale & Structure in Universe Universe is composed of voids and galaxy clusters. Voids could be millions of light years across.

  11. Nucleosynthesis of Light Elements • Hydrogen atoms: • the most common form of matter in the universe. • Atoms have mass. Clump together under gravity. • Formation of elements: • He through Fe (iron) inside stars (nuclear fusion) • Heavier elements in super-nova explosion (Fe & beyond)

  12. Formation of Large-Scale Structures Galaxies, like our Milky Way, are composed of stars, dust, gas and debris held together by gravity.

  13. Galaxies The Milky Way is approx. 100,000 light years in diameter. Our solar system is located on an outer spiral arm 27,000 light years from the galactic bulge. A black hole may be found within the bulge of the galaxy.

  14. Types of Galaxies Irregular Galaxy Spiral Galaxy Elliptical Galaxy (globular cluster)

  15. More Types of Galaxies

  16. Part 2: Origin Stars (Life Cycle of a Star)

  17. Life Cycle of a Star

  18. Life Cycle of a Star Step 1: All stars are born in nebulae. • Nebulae are clouds of dust & gas within galaxies. • Nebulae are concentrated in the arms of spiral galaxies.

  19. Types of Nebulae Supernova Nebula Dark Nebula

  20. Proto-stars • Proto-stars grow as hydrogen & helium gas are pulled together by gravity. • Proto-stars are not hot enough for fusion to occur. Artists rendition of a protostar

  21. As material continues to collect, the protostar gets hotter and hotter and hotter until . . . . . . Nuclear fusion begins and blows off the remaining gas (our first atmosphere)! Gamma & X-rays

  22. Stage 2: Main Sequence Star Our sun is a main sequence star (stable). It is a yellow dwarf star. Nuclear fusion of hydrogen gas into helium gas powers our Sun.

  23. Equation of Fusion e = mc2 4 H + 2e- 1 He + 2  + photons This is the nuclear reaction that happens inside stars and gives off massive radiation. All elements up to iron form inside stars, the remaining elements form during a supernova explosion.

  24. Bell Work 9-11-12 What event in a star’s life cycle changes a proto-star into a main sequence star? Nuclear Fusion occurs when the core temperature = 10 million degrees Kelvin

  25. Stage 3: Red Giant Stage • Hydrogen in the core is used up and fusion no longer balances gravity. • Star expands and collapses. • Gravity wins!

  26. Red Giant Stage - Unstable

  27. Stage 4 – Nova Stage

  28. Stage 5: White Dwarf Stage • All fuel is used up. • Dim, faint with high temperature. • Some Sun-like stars become white dwarfs made of carbon. • Some white-dwarfs flare up to a nova.

  29. Bell Work 9-12-12 Where do the following elements form? Hydrogen . . . Helium to iron . . . Elements heavier than iron . . . Big Bang Inside stars Supernova explosion

  30. Types of Stars Cool & Bright Hot & Bright Dying stars Our sun Dead stars Hot & Dim Cool & Dim HR Diagram

  31. Bell Work 9-13-12 Besides having life and abundant liquid water, what makes Earth different from the other terrestrial planets? Large moon Magnetic field High Density Plate Tectonics (volcanoes)

  32. Part 3: Origin of the Solar System

  33. Condensation Theory • The condensation theory explains how stars & planets are believed to be formed. • Condensation theory is based on the observation of stars and planets at different stages of development. • Scientists have inferred a sequence in which these stages occur.

  34. Origin of Our Solar System Metals (Fe, Mg, Al, Mn) & Rock (Si, K, Ca) – high melting points Gases like methane (CH4) and ammonia and solids like ice – low melting points 5 billion years ago: A solar nebula + shock wave & heavy atoms from a supernova= formation of solar system.

  35. Formation of Planets Terrestrial planets • New planets formed by a process called accretion, the clumping of small particles into large masses. • Accretion lasted about 30 to 50 million years. • As the sun began nuclear fusion, solar radiation swept past the inner planets clearing excess particles and stopping the accretion process. Planet formation Gas planets

  36. Our Solar System • Eight planets, asteroid belt, and icy bodies revolve around a star (our sun) in a plane. • Planet composition: • Inner 4 planets are terrestrial (rock/metal) • Outer 4 are gas giants (gas/ice) • Beyond Neptune are icy bodies (including Pluto) and asteroids.

  37. Terrestrial Planets Terrestrial planets are small, dense, and composed of rock. Venus is the hottest planet in the solar system due to run-away greenhouse effect. Mercury is a small, hot planet made mostly of iron.

  38. More Terrestrial Planets Mars is a dead planet with little atmosphere & evidence of liquid water on it’s surface. Terrestrial planets have few or no moons and no rings.

  39. Gas Planets Gas Planets are large, with low density, and composed of methane & ammonia gas.

  40. More Gas Planets Uranus & Neptune get their blue color from methane gas. Gas planets have lots of moons, rings, and no craters.

  41. Moons of Gas Planets Europa

  42. Moons of Gas Planets Titan Lakes of liquid methane

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