Chapter 1 – The Earth In Context
* Origin of the Universe (Beginning of the Universe)
* Started with the “Big Bang”
* Happened about 13.7 Billion Years Ago
* Doppler Effect – all celestial objects move away from each other. Supports the “Ever Expanding Uinverse Theory” * Scientists noticed that all stars & planets are moving away from Earth which supports the theory that a massive explosion once occurred. (Big Bang) * Red Light – a reddish color lights indicates that objects are moving away from Earth * Blue Light – a blue colored light indicates that objects are moving toward Earth * “Doppler” – the scientists who noticed that red light indicates a spreading effect (Ever Expanding Universe) * The first elements that were formed after the big bang are Hydrogen(H), Helium(He), Lithium (Li) , Beryllium (Be) , Boron (B) * These elements were formed by “Big Bang Nucleosynthesis” * Formation of Stars – form in clouds of interstellar clouds * Sufficient pressure, temperature, & energy are required to fuel Nuclear Fusion: 4H He + Energy
(Billions of stars were formed as a result of the above)
* Periodic Table has 92 naturally occurring elements today. * Stellar Nucleosynthesis – deals with the heavier elements * Low Mass Stars – Carbon (6)
* High Mass Stars - ?
* Stars - are Nuclear Fusion Reactors (Including the Sun) * Life Span of Stars – 5 to 10 Billion Years (Low Mass) * H (Hydrogen) fused to form Helium (He)
* Later Fusion of He(Helium) with the heavier elements occurs * Fe (Iron) – the heaviest element that can be produced through Fusion reactions within stars * Novas/Supernovas – Violent explosion of old stars
* Heavier elements form
* Residue of Novas/Supernovas is called Nebulae
* Nebulae – as the universe continued to expand & cool after the big bang occurred, atoms & molecules slowed down & accumulated into patchy clouds(Nebulae)
* Nebular Theory of Planet Formation
* 4.6 Billion Years Ago
* Proto-Planetary Disk spins in our part of the galaxy within the Nebula * Mainly consist of Gases & Interstellar Dust
* H, He, O, N, Si , Ca, Al , Na , K , MG , C, S, Fe * Gravity concentrated mass at the center of the protoplanetary disk * Gravitational Compression raised temperature to several million degrees causing a Thermo-Nuclear reaction 4H He + E : which formed the Sun * Formation of the Planets
* Condensation within the protoplanetary nebula: formation of planetesimals & later protoplanets. * Development of orbits
* Uptake of more materials (meteorites) from Nebula
* Solar System is about 5 Billion Years old.
* He fusion will continue for another 5 Billion Years
* Planetary Orbits are coplanar and all planets orbit in the same directions * Implies simultaneous planetary formation from swirling nebula that surround the sun * Planets accreted from nebula through gravitational attraction & collisions * We have 8 planets in our solar system – Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune * Terrestrial Planets – Mercury, Venus, Earth, Mars – closer to the sun; rocky (remember “VEMM” * Jovian Planets – Jupiter, Saturn, Uranus, Neptune – Gas Giant Planets: outer planets; mostly consist of gas and ice; very large planets * Basic difference between Terrestrial and Jovian Planets is the temperature gradient away from the Sun * Terrestrial Planets – has elements that condense at high temperatures (Ca, Al, FE, NI, Co , Mg , Si) * Differentiation – heavier elements move towards the center (Fe ,Ni) * Differentiation leads to the layered structure of planets * Lighter elements were lost in space (H, He)
* Pluto is part of the Kuiper Belt which is...