4.3 Earth and Space Sciences: Geology, Meteorology, and Astronomy

Earth and Space Sciences: Geology, Meteorology, and Astronomy

Earth and Space Sciences examine the dynamic processes shaping planet Earth and its cosmic environment. LET candidates must understand solid Earth geology, atmospheric weather patterns (specifically in the Philippine archipelago), and celestial astronomy.

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1. Solid Earth Geology and Plate Tectonics

Earth is structured in concentric layers defined by chemical composition and physical properties.

Layers of the Earth

1. Crust: Thin, outermost rigid layer.
   • Continental Crust: Thicker (30-50 km), less dense, composed primarily of granite.
   • Oceanic Crust: Thinner (5-10 km), denser, composed primarily of basalt.
2. Mantle: Comprises ~84% of Earth's volume. Includes the upper mantle's ductile asthenosphere, upon which tectonic plates float.
3. Outer Core: Liquid iron and nickel alloy. Convection currents here generate Earth's magnetic field.
4. Inner Core: Solid sphere of iron and nickel maintained under extreme pressures despite temperatures reaching 5,400°C.

Plate Tectonics and Boundary Dynamics

The theory of Plate Tectonics explains that Earth's lithosphere is fragmented into major plates that move over the asthenosphere due to mantle convection currents.

Note: The Philippines lies along the Pacific Ring of Fire, making it highly vulnerable to volcanic eruptions (e.g., Mt. Pinatubo, Taal Volcano, Mayon Volcano) and seismic earthquake activity.

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2. The Rock Cycle

The Rock Cycle illustrates how geological processes continuously transform three primary rock classifications:

                  IGNEOUS ROCK
                 /            \
      Cooling & /              \ Weathering &
  Crystallization               \ Erosion
               /                 v
      MAGMA / LAVA            SEDIMENTS
               ^                 |
      Melting   \                | Compaction &
                 \               v Cementation
             METAMORPHIC ----> SEDIMENTARY
                ROCK    Heat &    ROCK
                       Pressure

1. Igneous Rocks: Formed from the cooling and solidification of molten rock.
   • Intrusive (Plutonic): Cools slowly beneath Earth's surface, producing large coarse crystals (e.g., Granite, Diorite).
   • Extrusive (Volcanic): Cools rapidly on Earth's surface, producing fine-grained or glassy textures (e.g., Basalt, Obsidian, Pumice).
2. Sedimentary Rocks: Formed from the weathering, erosion, deposition, compaction, and cementation (lithification) of rock fragments or organic matter (e.g., Limestone, Sandstone, Shale). Fossils are found almost exclusively in sedimentary rocks.
3. Metamorphic Rocks: Formed when existing rocks are subjected to high heat and extreme pressure without melting, altering their mineral structure (e.g., Marble derived from limestone, Slate derived from shale).

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3. Meteorology and Philippine Weather Dynamics

Layers of the Atmosphere

Monsoons (Salit-salit na Hangin) in the Philippines

The Philippines experiences two distinct seasonal monsoon wind regimes driven by differential heating of landmasses and oceans:

• Northeast Monsoon (Amihan):
  • Months: November to February.
  • Characteristics: Cold, dry winds originating from high-pressure systems in Siberia and mainland China.
  • Impact: Brings cool weather and rains to eastern coastal provinces of Luzon and Visayas.
• Southwest Monsoon (Habagat):
  • Months: May to October.
  • Characteristics: Warm, moist, rain-bearing winds originating from the Indian Ocean and South China Sea.
  • Impact: Brings heavy rainfall, torrential storm surges, and flooding across western Philippines.

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4. Astronomy and Earth-Moon-Sun Dynamics

The Solar System

• Sun: G2V main-sequence star powered by nuclear fusion ($4,^1\text{H} \rightarrow ,^4\text{He} + \text{Energy}$) in its core.
• Planetary Order from the Sun: Mercury, Venus, Earth, Mars (Terrestrial / Rocky Inner Planets), Jupiter, Saturn, Uranus, Neptune (Jovian / Gas and Ice Giants).

Motions of the Earth and Celestial Phenomena

• Rotation: Earth spinning on its axis ($23.5^\circ$ tilt) once every 24 hours. Causes Day and Night.
• Revolution: Earth orbiting the Sun along an elliptical path once every 365.25 days. Combined with axial tilt, this causes Seasons.

Solar vs. Lunar Eclipses