Earth and Science First Summative

🌍 EARTH SCIENCE REVIEWER

📌 I. MODELS OF THE UNIVERSE

Geocentric Model

• Proposed by Aristotle and Ptolemy

• Belief that the Earth is at the center of the universe.

Heliocentric Model

• Proposed by Nicholas Copernicus

• Stated that the Sun is at the center of the solar system.

Atomic Universe

• Proposed by Leucippus and Democritus

• Universe is made up of indivisible, indestructible atoms.

📌 II. UNIVERSE EXPANSION

Red Shift

• Seen in far galaxies.

• Light stretches → turns red → means the galaxies are moving away.

• Supports the expanding universe theory.

Blue Shift

• Seen in closer galaxies.

• Light compresses → turns blue → means galaxies are approaching us.

📌 III. BIG BANG TIMELINE (IN ORDER)

• 10⁻³⁶ seconds – Quantum fluctuations begin the universe.

• 10⁻³⁵ to 10⁻³³ seconds – Inflation: extremely rapid expansion of the universe.

• 10⁻⁶ seconds – Formation of elementary particles (quarks, electrons, etc.).

• 10⁻¹⁰ to 0.001 seconds – Nucleosynthesis: atomic nuclei begin to form.

• 3 minutes – Chemical elements like hydrogen and helium form.

• 5000 years later – Atoms formed; release of cosmic microwave background radiation.

📌 IV. KEY UNIVERSE CONCEPTS

Baryonic Matter

• Regular matter made of atoms, protons, neutrons, and electrons.

• Makes up stars, planets, humans — everything we can touch and see.

Dark Matter

• Invisible matter we cannot detect with light.

• Makes up most of the universe's mass.

• Only detected by its gravitational effects.

Energy

• The ability to do work or cause change.

• Comes in many forms: heat, light, motion, electricity, chemical, nuclear.

Light Year

• The distance light travels in one year.

• Equals about 9.46 trillion kilometers.

• Used to measure distances between stars and galaxies.

📌 V. STAR FORMATION

Protostar

• A cloud of gas and dust in space that begins to collapse under gravity.

• The first stage in the formation of a star.

Thermonuclear Reaction

• Process in which hydrogen atoms fuse to form helium, releasing massive energy.

• This reaction powers stars like the Sun.

📌 VI. 10 CHARACTERISTICS OF EARTH THAT SUPPORT LIFE

Liquid Water

• Exists in all three states: solid, liquid, gas.

• Acts as a universal solvent.

• Covers 70% of Earth's surface.

Right Distance from the Sun

• Not too hot, not too cold — just right to keep water in liquid form.

Plate Tectonics

• Earth's crust is broken into moving plates.

• Helps recycle nutrients and shape the Earth’s surface.

Right Size

• Large enough to retain an atmosphere and support life.

• Proper size keeps internal heat and magnetic field active.

Correct Gravity Strength

• Keeps the atmosphere in place.

• Helps in water cycling and biological functions.

Atmosphere

• Made of 78% nitrogen, 21% oxygen, and 1% other gases.

• Protects from UV radiation (ozone layer).

• Traps heat, maintaining Earth's stable temperature.

Moon

• Helps stabilize Earth’s rotation.

• Prevents extreme axis tilts that would disrupt climate.

Magnetosphere

• Earth’s magnetic field protects us from solar wind and cosmic radiation.

• Shields the surface and atmosphere.

Energy Source

• The Sun powers life through photosynthesis.

• Energy from sunlight supports the entire food chain.

Time

• Earth is 4.6 billion years old.

• Life had time to evolve because our Sun burns for billions of years.

📌 VII. EARTH'S SUBSYSTEMS (SPHERES)

Geosphere

• The solid Earth — rocks, minerals, landforms, crust, mantle, and core.

Hydrosphere

• All water on Earth — oceans, lakes, rivers, glaciers, groundwater, and vapor.

Atmosphere

• The layer of gases that surrounds Earth.

• Provides oxygen, regulates climate, and protects from radiation.

Biosphere

• All living things — animals, plants, fungi, and microorganisms.

📌 VIII. THE HELIOSPHERE

• A bubble-like region in space dominated by the solar wind from the Sun.

• Encloses the solar system and protects it from interstellar radiation.

• The boundary is called the heliopause.

✅ QUICK TIPS TO REMEMBER

• Models: Geocentric → Heliocentric → Atomic

• Big Bang: Fluctuations → Inflation → Particles → Nuclei → Elements → Atoms

• Earth's Subsystems: Geosphere, Hydrosphere, Atmosphere, Biosphere, Cryosphere

• Key Forces: Gravity, Magnetism, Nuclear Fusion (in stars)

📌 IX. THE SOLAR SYSTEM AND THE 8 PLANETS

The Solar System

• Located in the Milky Way Galaxy.

• Consists of the Sun, 8 planets, their moons, and smaller objects like asteroids and comets.

• The planets are held in orbit by the Sun’s gravity.

Mercury

• Closest to the Sun; smallest planet

• No atmosphere and no moons

• Rotates every 59 Earth days

• Revolves around the Sun in 88 days

• Average temperature: 167°C

• Composed mainly of iron and silicate rock

Venus

• Second planet from the Sun; similar in size to Earth

• Thick, toxic atmosphere rich in carbon dioxide

• Rotates in 243 Earth days (retrograde rotation)

• Revolves around the Sun in 225 days

• Average temperature: 464°C (hottest planet due to greenhouse effect)

• Atmosphere composed of carbon dioxide and sulfuric acid

Earth

• Third planet; the only known planet to support life

• Has a breathable atmosphere and one moon

• Rotates every 24 hours

• Revolves around the Sun in 365.25 days

• Average temperature: 15°C

• Atmosphere made of nitrogen and oxygen

Mars

• Fourth from the Sun; called the Red Planet due to iron oxide

• Has a thin atmosphere and two small moons

• Rotates every 24.6 hours

• Revolves around the Sun in 687 days

• Average temperature: -63°C

• Composed mainly of carbon dioxide and iron oxide

Jupiter

• Fifth planet; largest in the solar system

• Gas giant with at least 79 moons

• Rotates every 10 hours (fastest rotation)

• Revolves around the Sun in 12 Earth years

• Average temperature: -110°C

• Composed mainly of hydrogen and helium

Saturn

• Sixth planet; famous for its large ring system

• Gas giant with over 80 moons

• Rotates every 10.7 hours

• Revolves around the Sun in 29.5 years

• Average temperature: -140°C

• Composed mainly of hydrogen and helium

Uranus

• Seventh planet; blue-green color due to methane gas

• Ice giant that rotates sideways (tilted axis)

• Rotates every 17.2 hours (retrograde)

• Revolves around the Sun in 84 years

• Average temperature: -195°C

• Composed of hydrogen, helium, and methane

Neptune

• Eighth and farthest planet from the Sun

• Deep blue color with the fastest winds in the solar system

• Rotates every 16 hours

• Revolves around the Sun in 165 years

• Average temperature: -200°C

• Composed of hydrogen, helium, and methane

🔭 Rotation = how long a planet takes to spin on its axis (day)

☀ Revolution = how long a planet takes to orbit the Sun (year)

♻ Retrograde rotation = spins opposite direction (Venus, Uranus)

🔥 Inner planets are rocky and warmer

❄ Outer planets are gaseous or icy and colder

🧠 Mnemonic

My Very Educated Mother Just Served Us Noodles

→ Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune