Stars and Volcanoes

• The Sun has a: Radius of 695,500 km

  • Mass of 1.988 x 10^30kg
  • Core: 15M degrees C
  • Photosphere: 6K°C
  • Corona: 2M°C
• Bursts of energy are often emitted by the sun, called solar storms
• Thanks to the Earth's magnetosphere, the sun's solar storms don't harm us
• Solar Wind


  Light particles emitted by the solar storms
• Solar Flare


  Explosion of gas from the Corona
• Auroras


  Caused by light particles from the solar wind when they collide with the atoms of oxygen and nitrogen from the Earth's atmosphere (Magnetosphere)
• Auroras


  • Borealis: Northern Lights
  • Australis: Southern Lights
• The Life Cycle of Stars

  1. Stars from stellar nebula: gravity starts to pull the hydrogen and it will begin to spin

  2. As it spins faster, heat is radiated

  3. Nuclear fusion will occur in the cloud's core and soon form a main sequence star
• Main Sequence stars


  Stable stars that fuse hydrogen to form helium atoms
• Nuclear Fusion


  1. As the stellar nebula turns into a protostar, the core reaches a high temperature (approx. 15M degrees Celsius)

  2. The hydrogen found in the core (which was pulled in by gravity) will be a plasma of hydrogen ions and electrons moving around at a very high speed

  3. Inside the core, the temperature and density levels are extremely high which results in tightly packed protons which are rapidly moving

  4. As the temperature increases and increases, the protons can't help but collide with each other due to its rapid movement, causing a fusion, a release of energy
• The Life Cycle of Stars

  1. The cloud starts to glow, contract a little, and become stable

  2. The hydrogen in the core is then converted into helium (because of nuclear fusion)

  3. The outer shell starts to expand and as it expands, it cools

  4. The star is now a red giant

  5. If the helium in the core runs out, the core becomes unstable and the star will no longer generate heat
• Red Giant/Red Super Giant Stars

  • Low mass: Sun-like stars turn into a red giant, carbon is formed through the fusion of helium, core collapses again, outer layers are expelled, turns into a planetary nebula, the core remains as a white dwarf and soon turns into a black dwarf
  • High mass: Larger stars and giant stars turn into a super red giant, supernova explosion
• Supernova explosion


  Neutron star is formed when remnants of the explosion are 1.4-3 times as massive as the sun, gravity overcomes the nuclear forces and it becomes a neutron star or a black hole
• The bigger the star, the more violent death it can create
• Characteristics of stars


  • Size: The size of a star is directly proportional to its brightness or luminosity, larger stars have a greater surface area, meaning they have the capability to produce big amounts of energy, resulting in a greater luminosity
  • Mass: The mass of a star is also directly proportional to its temperature, the more mass a star has, the force of gravity pushing inward towards the core increases, which results in a hotter temperature
  • Color: The color of the star ranges from red, yellow, to blue, this depends on its temperature, bluish stars are hotter, while reddish stars are cooler
• The larger the mass, the shorter the life cycle
• Type stars are the hottest, Type M stars are the coolest
• Apparent Motion


  The way we see things in the sky based on Earth's movements
• Apparent Motion

  • Rotation: on its axis (West to East)
  • Tilt of the earth on its axis
  • Revolution: Earth's orbit
• Based on Earth's movements, the Sun and other stars rise in the east, and set in the west
• The reason why scientists describe the earth as a young planet is that a lot of natural calamities happen underneath and on the surface like volcano eruptions, earthquakes, typhoons, and more
• Volcanoes


  Vent/hill/mountain that erupts, releasing molten rocks, rock fragments, and gaseous materials, formed by plate movements like colliding, spreading, and rubbing, mostly formed by colliding tectonic plates
• Anatomy of a Volcano

  • Main Vent: magma passes through magma chamber
  • Magma Chamber: large reservoir that stores molten rock
  • Crate: bowl-shaped depression
  • Lava flow: molten rock flowing out of the crater
  • Secondary Vent: alternative smaller outlet
  • Secondary Cone: known as parasitic cones
  • Ash Cloud: Thick volcanic ashes are discharged
• Types of Volcanoes (Structure)

  • Cinder Cone: Volcanoes that are formed by pyroclastic fragments and ashes that form and solidify around the main vent, example: Taal Volcano
  • Composite: Also fires out fragments and ash, the tallest type of volcano, acidic and sticky lava functions as a base, example: Mayon Volcano
  • Shield: Non-acidic basaltic lava, not very explosive and are among the largest volcanoes, formed by cooling lava flow, example: Hawaiian volcanoes, some islands are also formed by shield volcano eruptions
• Types of Volcanoes (Activity)

  • Active: Erupted in the last 100 years
  • Dormant: Active but not erupting, erupt anytime soon
  • Extinct: No eruption in the past 10,000 years
• Pyroclastic Materials


  • Ash: can harm animal and human respiratory health
  • Cinder: compounds that fly out of the crater that can burn anything in its path
• PHIVOLCS

  Philippine Institute of Volcanology and Seismology
• NDRRMC

  National Disaster Risk Reduction Management Council
• Phases of an Eruption

  1. Preparation: Magma chamber gets filled with magma, increase in seismic activity, steam is observed

  2. Eruption: Pressure builds up and energy increases, magma is pushed up to the opening due to the explosion of pent-up gasses, rock fragments, pyroclastic materials, gasses, ashes

  3. Ending: Magma cools and becomes lava once reaching the surface, the magma chamber is empty, walls are triggered and weaken, walls collapse into a crater/caldera
• Types of Eruptions


  • Effusive: outpouring of basaltic lava which is low in viscosity
  • Explosive: magma of high viscosity and high gas content
  • Hawaiian: Fluid basaltic lava is thrown in the air, and often forms into shield volcanoes
  • Strombolian: a burst of glowing lava due to the bursting of gas bubbles at the vents of the volcano, creates eruptive products like scoria and lava bombs
  • Vulcanian: eruption is short, explosive, and violent, pressure is enough to blow off the overlying layer of solidified lava over the entrapped gases in magma
  • Plinian: most violent among all types of volcanic eruptions, releases huge amounts of gases and ashes at great speeds
  • Phreatic: steam-driven explosion, often precede or accompany another type of volcanic eruption
  • Phreatomagmatic: involves the eruption of magma that reacts to external water, the interaction between magma and water results in an explosion that releases steam and pyroclastic fragments into the Earth's surface