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Learn about the Big Bang Theory and how it led to the formation of our Solar System. Explore the Nebular Hypothesis and the origin of terrestrial planets. Discover the age of the Earth and the processes that shaped it.
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Solar System History Big Bang Theory Solar Nebula Planetesimals Terrestrial Planets
Big Bang Hypothesis 13-14 billion years ago, all matter and energy was concentrated into a single, inconceivably small (and very dense) point. This hypothesis stems from a mathematical solution to the problem This hypothesis was tested through the Doppler shift in stellar spectrum, which implied that matter was flying apart in all directions throughout the universe
The Hubble Telescope Can detect faint light that has travelled for billions of years, …. from the start of the current universe
Nebular Hypothesis and the origin of our Solar system • Older than 4.56 billion years ago • Gravity is the first force in the solar system formation • Cloud contracted WHILE spinning ever faster • H and is the most common element (gas) • H fuses to form He
Nebular Hypothesis and the origin of our Solar system • Fusion is more energetic than atomic fission but requires greater pressures/heats • 4 Hydrogen nuclei fuse to create He
Nebular Hypothesis and the origin of our Solar system • Planetesimals (early-stage, immature, small planets) on the periphery of this contracting, spinning dust cloud began to clump together locally. • Denser materials fell closer to the sun (terrestrial planet formation) • Less dense materials (gases) could escape to greater distances from the sun e,.g., Saturn floats in water
Nebular Hypothesis and the origin of our Solar system • Mercury, Venus, Earth, Mars are called the terrestrial planets • Rocky crust • Metalic core
Size of the Planets Fig. 9.3
How old is the Earth? Younger than the planetesimals 4.56 by
How old is the Earth? Older than the moon ……… oldest rocks are4.47 by …... the moon started to form earlier … 4.5 by
What was happening between 4.56 and 4.5 by ? • (1) Accretion to create the first earth… a “magma” earth (100 million-year-period
What happened to the Earth at 4.5 by ? • Earth was hit by a giant bolide (before 4.47 by) that remelted it and led to the formation of the moon
What was happening between 4.5 and 4.4 by ? • (1)Mainly cooling and differentiation: Gravity pulled the denser materials toward the core Fe and Ni when the Earth was still molten • Lighter oxygen and silicon rose to form the crust