Earth Systems Module 1 and 2

Formation of the Universe

• Big Bang Theory indicates the universe began as a hot, small entity and expanded explosively approximately 13.7 billion years ago.
• Red shift phenomena show distant galaxies moving away, supporting the idea of an expanding universe.
• Steady State Theory posits that the universe maintains constant average density while expanding.
• Cosmic Inflation Theory suggests rapid expansion of the universe occurred in its early stages due to pure vacuum energy.
• Edwin Hubble demonstrated that the farther away a galaxy is, the faster it is receding, providing evidence for cosmic expansion.

Formation of the Star Systems

• Nebular Hypothesis is the prevailing model explaining how the solar system formed and evolved from a cloud of gas and dust.
• Planetesimal and Tidal Series theory asserts that planets revolve in the same direction, with inner planets possessing greater density than outer ones.
• William Huggins discovered that stellar light emitted is often shifted to longer wavelengths, reinforcing the concept of redshift.

Earth's Internal Structure

• Crust comprises oceanic and continental layers, with thickness ranging from 5 to 70 km.
• Mohorovicic Discontinuity (Moho) separates the crust from the underlying mantle, marking a significant transition.
• Mantle lies beneath the crust and is divided into several sub-layers.
• Asthenosphere is a sub-layer of the mantle, serving as the source of magma that rises through the crust.
• Lithosphere encompasses the solid outer layer of Earth, including both the crust and the upper mantle.
• Gutenberg Discontinuity is the boundary separating the lower mantle from the outer core.
• Core primarily consists of iron and nickel, representing the innermost layer of the Earth.
• Lehman Discontinuity identifies the transition between the outer core and the inner core.