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• Georges Lemaître, a Belgian Catholic priest and physicist, developed the Big Bang theory, suggesting the universe began from a single primordial atom
• The Big Bang Theory explains the universe starting with a small singularity, then inflating over 13.8 billion years to the cosmos we know today
• The Steady State Theory claims the universe is always expanding with a constant average density and has no beginning or end, but it's now rejected by most cosmologists
• The Cosmic Inflation Theory supports the Big Bang Theory, proposing that the early universe was a rapidly expanding bubble of pure energy
• The Nebular Hypothesis explains that the solar system formed from the collapse of a giant cloud of gas and dust, with the hot central region becoming the sun and the surrounding materials forming planets
• The Planetesimal Theory suggests that about 5 billion years ago, a great cloud of gas and dust rotated slowly in space, eventually forming solid bodies called planetesimals
• Earth's atmosphere contains 78% nitrogen, 21% oxygen, and 1% argon, with atmospheric layers including the troposphere, stratosphere, mesosphere, thermosphere, and exosphere
• The Nebular Hypothesis explains how stars and planets form from the collapse of a giant cloud of gas and dust, with the material in the center forming a star and the outer part forming planets

  
• The Earth's internal structure includes the crust, mantle, outer core, and inner core, as well as the lithosphere, asthenosphere, and mesosphere

  
• Factors for life to thrive on Earth and other worlds:

  • Water is a crucial solvent
  • Energy sources are essential, like sunlight for photosynthesis
  • Time for evolution, with stars living long enough for life to evolve
  • Recycling processes like plate tectonics are vital
  • Bonus features like stable radiation from the sun and a protective magnetic field
• The Earth's atmosphere is composed of 78% nitrogen, 21% oxygen, 0.9% argon, 0.03% carbon dioxide, and trace amounts of other gases
• The biosphere includes all parts of Earth where life exists, from root systems to ocean trenches and mountaintops
• The lithosphere is the solid, outer part of the Earth, including the crust and the top part of the mantle
• The hydrosphere comprises the Earth's liquid water, covering about 70% of the Earth's surface and divided into freshwater and saltwater
• Rocks are made up of minerals, which are naturally occurring solid substances with a definite chemical composition
• Physical properties used to identify minerals include color, streak, hardness, cleavage, crystalline structure, transparency, magnetism, tenacity, luster, odor, and specific gravity
• The Mohs scale is used to measure the hardness of minerals, graded from 1 to 10, with 10 being the hardest and 1 the softest
• Georges Lemaître, a Belgian Catholic priest and physicist, developed the Big Bang theory

  
• The Nebular Hypothesis explains how stars and planets form: a giant cloud of gas and dust collapses, rotates, flattens into a disk, with the densest and hottest material forming a star and the outer part forming planets

  
• A cutaway view of the earth reveals its internal structure, including the crust, mantle, outer core, inner core, lithosphere, asthenosphere, and mesosphere

  
• Fluorite is a calcium fluoride mineral found in various colors, used in applications like steel production and hydrofluoric acid manufacturing

  
• Crystalline solids have atoms, molecules, or ions arranged in a regular, repeating pattern, giving them characteristic properties like shape, hardness, and melting point

  
• Mineral properties:

  • Cleavage and fracture describe how minerals break into pieces, with cleavage being a smooth break along the crystalline structure and fracture occurring where there is no cleavage
  • Crystalline structure indicates how a mineral's crystals are arranged, with silicate minerals being the largest and most abundant group containing silicon, oxygen, and other elements
• Mineral identification:

  • Transparency or diaphaneity indicates the extent of light passing through a mineral
  • Magnetism shows a mineral's ability to attract or repel other minerals
  • Tenacity reveals a mineral's resistance to stress like crushing or bending
  • Luster refers to a mineral's reaction to light, determining its brilliance
  • Odor is the distinct smell released by a mineral when subjected to water, heat, air, or friction
  • Specific gravity measures a mineral's density and weight compared to water
• Chemical properties of minerals:

  • Minerals are classified based on their chemical composition, with eight basic classes like silicate, carbonate, sulfate, and oxide
• Rock classifications:

  • Rocks are categorized into igneous, sedimentary, and metamorphic types based on their formation process
  • Igneous rocks form from the solidification of molten rock material, either below the Earth's surface (plutonic) or at the surface (volcanic)
• The Nebular Hypothesis explains how stars and planets form from the collapse of a giant cloud of gas and dust, which flattens into a disk where the densest and hottest material forms a star, while the outer part forms planets

  
• Igneous rocks form from the solidification of molten rock material (magma or lava) either below the Earth's surface (plutonic igneous rocks) or at the surface (volcanic igneous rocks)
• Minerals are formed during the crystallization of magma, with the rate of cooling being a crucial factor that controls crystal size and the texture of the rock
• Sedimentary rocks form through the accumulation, compaction, and cementation of sediments, with common features including strata (bedding and lamination) and fossils
• Metamorphic rocks form from the transformation of pre-existing rocks through metamorphism, involving changes in physical and chemical properties in response to heat, pressure, and chemically active fluids
• The lithosphere is the solid, outer part of the Earth, including the brittle upper portion of the mantle and the crust, the outermost layers of Earth's structure
• The hydrosphere covers about 70% of the Earth's surface and is the home for many plants and animals, divided into freshwater and saltwater
• The atmosphere is composed of 78% nitrogen, 21% oxygen, 0.9% argon, 0.03% carbon dioxide, and trace amounts of other gases
• Silicate minerals are the largest and most abundant group containing silicon and oxygen with some aluminum, magnesium, iron, and calcium
• The Big Bang theory explains the universe starting with a small singularity and inflating over 13.8 billion years to the cosmos we know today
• The Cosmic Inflation theory supports the Big Bang Theory, stating that the early universe is a rapidly expanding bubble of pure energy
• The Nebular Hypothesis is a scientific theory explaining how stars and planets form from the collapse of a giant cloud of gas and dust
• The Steady State theory claims the universe is always expanding with no beginning or end, and its appearance remains the same over time
• The Biosphere is the part of Earth where life exists, extending from the deepest root systems of trees to high mountaintops