Earth Science

• Habitable planet


  A planet that can sustain life for a significant period of time, requiring liquid water
• Earth


  • The only planet known to support life
• The magnetic field is extremely important to sustaining life on Earth. Without it, we would be exposed to high amounts of radiation from the Sun and our atmosphere would be free to leak into space.
• This is likely what happened to the atmosphere on Mars.
• Mission Artemis


  NASA will land the first woman on the Moon, using innovative technologies to explore more of the lunar surface than ever before establishing the first long-term presence on the Moon. Then, learnings and discoveries around the Moon will be used in the next giant leap: sending the first astronauts to Mars.
• Mission: Mars 2020


  NASA's Perseverance Mars rover landed on the Red Planet on Feb. 18, 2021. Perseverance's mission on Mars is astrobiology, the search for signs of ancient microbial life. The rover will characterize the planet's geology and past climate, pave the way for human exploration of the Red Planet, and be the first mission to collect Martian rock.

  
• Earth's crust


  • Extremely thin, cold and brittle made of relatively light elements, especially silica, aluminum and oxygen
  • Highly variable in thickness, 5 km under oceans, 30-70 km under continents

  
• Mohorovičić Discontinuity


  Boundary or surface with seismic waves that change velocity, named after Andrija Mohorovičić, a Croatian seismologist who discovered its existence
• The deepest humans have ever drilled is just over 12 km (7.6 mi) which took 20 years.
• The thickest part of Earth's crust is about 70 km (43 mi) thick and lies under the Himalayan Mountains.
• Earth's mantle


  • Lies beneath the crust and extends to a depth of 2,900 km, made up of very hot and dense rocks which flow due to great differences in temperature moving from the bottom to the top, called convection currents

  
• Earth's core


  • Divided into a solid inner core and a liquid outer core
  • Inner core is an extremely dense, solid metal ball with a radius of 1,220 km, made mostly of iron and nickel
  • Outer core is made from iron and nickel, in liquid form, sitting 5,180 to 2,880 km below the surface, heated largely by the radioactive decay of uranium and thorium

  
• Earth's magnetic field is caused by a dynamo effect. The earth's liquid outer core motion generates electrical currents that generates the earth's magnetic field.
• Dynamo effect


  The same process as a dynamo light on a bicycle, where magnets in the dynamo start spinning when the bicycle is pedaled, creating an electric current which is then used to turn on the light. This process also works in reverse, where a rotating electric current will create a magnetic field.
• Mars doesn't have flowing liquid metal in its core, it doesn't produce the same dynamo effect. The red planet has a very weak magnetic field, allowing for its atmosphere to be stripped away by solar winds, leaving it uninhabitable.
• The inner core spins a bit faster than the rest of the planet. It's also intensely hot: Temperatures sizzle at 5,400° C (9,800° F) almost as hot as the surface of the sun, 3 million times greater than on Earth's surface.
• How we know about Earth's deeper layers

  Scientists know a great deal about Earth's inner structure by studying how earthquake waves travel through the planet. The speed and behavior of these waves change as they encounter layers of different densities. They have also learned about the core and mantle from calculations of Earth's total density, gravitational pull and magnetic field.

  
• Subsystems of the Earth

  • Lithosphere
  • Hydrosphere
  • Atmosphere
  • Biosphere
• Lithosphere


  • The rigid, outermost shell on Earth, composed of the crust and the portion of the upper mantle

  
• Hydrosphere


  • Composed of all the waters in the Earth, including the oceans, seas, rivers, lakes, and even the moisture in the air
• Atmosphere


  • The mass of air surrounding our planet, subdivided into different layers of different densities
  • Most of the gas is nitrogen (78%) or oxygen (21%), with the remaining 1% a mixture of other gases
  • The "thickest" air is right above Earth's surface, becoming increasingly thinner with increasing altitude due to gravity pulling the air molecules down
• Biosphere


  • Composed of all living things, from the deepest oceans to the upper atmosphere, including all the air, land and water where life exists
• Mineral


  A solid, inorganic substance of natural occurrence
• Rock


  A conglomerate of various minerals formed on Earth's surface

  
• Rock


  • Composed primarily of grains of minerals
  • 3 types: Igneous, Sedimentary and Metamorphic

  
• Ore


  Naturally-occurring solid where valuable metals or minerals are extracted for profit
• The most valuable ores contain metals crucial to industry and trade, like Cu, Au, and Fe
• Characteristics of minerals


  • Naturally occurring
  • Inorganic
  • Solid
  • Can be represented by a chemical formula
• The only mineral formed through organic processes is Calcite (CaCO3)
• If you squeeze a quartz crystal, it generates a tiny electric voltage. The opposite is also true: if you apply a voltage to a piece of quartz, it vibrates at a precise frequency. This ability is called "Piezoelectric effect"
• Steel, Pearl, Bronze, Mercury, and Obsidian are not considered minerals
• How pearls are formed

  When an irritant works its way into a particular species of oyster, mussel, or clam, the mollusk secretes a fluid to coat the irritant. Layer upon layer of this coating is deposited on the irritant until a lustrous pearl is formed.
• Properties for identifying the type of mineral

  • Optical properties (luster, color, streak)
  • Strength (tenacity, hardness, cleavage, fracture)
  • Specific gravity

  
• Streak is more reliable than color in identifying the color of a mineral

  
• Flat surfaces that are formed from breakage are called cleavage. Minerals that do not exhibit cleavage planes have strong chemical bonds between atoms.
• Specific gravity is a measure of the density of minerals, comparing the weight of the mineral to the same volume of water.
• Creationism


  The belief that the universe and the various forms of life were created by God out of nothing
• Hindu triumvirate


  • Consists of three gods - Brahma, Vishnu and Shiva - who are responsible for the creation, upkeep and destruction of the world
  • Vishnu is the preserver of the universe
  • Shiva's role is to destroy it in order to re-create
  • Brahma's job was creation of the world and all creatures
• Brahma's name should not be confused with Brahman, who is the supreme God force present within all things
• Japanese creation myth


  • Centered around the couple Izanagi and Izanami
  • Izanagi dipped his spear and swirled the waters, forming the islands of Japan
  • When Izanami died, it broke Izanagi's heart
  • Upon their furious quarrel in the Underworld, his saddened heart slowly trod to the baths