UPCAT General Science (Extended) — Universe, Solar System & EarthCheat Sheet
A printable cheat sheet for Universe, Solar System & Earth, built for UPCAT reviewers who want one go-to reference in the final stretch. Covers formulas, key definitions, common question types, and the University of the Philippines-specific twists you will see on UPCAT day.
Exam context
On the UPCAT 2026, the General Science (Extended) subtest carries a "Extended coverage for UP Science programs" weight in University of the Philippines's pattern. Universe, Solar System & Earth lands at position 3rd out of 6 in the standard review order. Target score is UPG ≤ 2.2 typical, and roughly 20 items come from General Science (Extended) on a typical UPCAT paper.
Universe, Solar System & Earth - Cheat sheet
Your last-minute revision companion for Chapter 29 - comprehensive quick reference for Universe, Solar System & Earth topics
Sections
Common Values
Value
13.7 billion years
Symbol
t
Quantity
Age of Universe
Value
≥91 billion light-years
Symbol
d
Quantity
Universe diameter
Value
9.4607 × 10^12 km
Symbol
ly
Quantity
Light year
Section Title
Big Bang Theory & Universe Formation
Important Facts
- Universe is 13.7 billion years old
- Diameter is at least 91 billion light-years
- Composed of 4.6% baryonic matter, 24% dark matter, 71.4% dark energy
- Three most abundant elements: Hydrogen, Helium, Lithium
- Planck epoch: 10^40 K, immediate after Big Bang
- Helium was the first element formed in the universe
Key Definitions
Term
Big Bang Theory
Example
Explains why galaxies are moving away from each other
Definition
Universe began as a singularity 13.7 billion years ago, then exploded creating energy, space, time, and matter
Term
Singularity
Example
Initial state of the universe
Definition
Hot, infinitely dense point just a few millimeters in size before the Big Bang
Term
Radiation Era
Example
Planck epoch to Nuclear epoch
Definition
First stage after Big Bang dominated by high-energy particles and radiation
Term
Matter Era
Example
Atomic epoch to Stellar epoch
Definition
Stage when matter became dominant, leading to formation of elements and structures
Diagrams To Know
- Big Bang Timeline diagram
- Universe composition pie chart
- Radiation Era vs Matter Era comparison
Common Values
Value
4.568 billion years
Symbol
age
Quantity
Solar System Age
Value
150 million km
Symbol
AU
Quantity
Astronomical Unit
Value
240 million years
Symbol
T
Quantity
Galactic Revolution
Section Title
Solar System Formation
Important Facts
- Solar system is 4.568 billion years old
- Located in Milky Way galaxy (100 million light-years across)
- Revolves around galactic center once every 240 million years
- Inner planets: rocky, thin atmosphere, high density
- Outer planets: gas giants, thick atmosphere, low density
- 1 AU = Sun-Earth distance = 150 million km
Key Definitions
Term
Solar System
Example
Our cosmic neighborhood formed 4.568 billion years ago
Definition
Sun, 8 planets, dwarf planets, satellites, asteroids, comets, and other minor bodies
Term
Asteroid Belt
Example
Failed planet due to Jupiter's gravitational interference
Definition
Region between Mars and Jupiter containing rocky remnants
Term
Kuiper Belt
Example
Where Pluto is located
Definition
Region beyond Neptune (30-50 AU) with rocky/icy bodies
Term
Oort Cloud
Example
Source of long-period comets
Definition
Outer boundary of solar system composed of icy objects
Diagrams To Know
- Solar system structure diagram
- Planet classification chart
- Asteroid belt and Kuiper belt positions
Common Values
Value
1,800 miles (2,900 km)
Symbol
h
Quantity
Mantle thickness
Value
80% of Earth's volume
Symbol
%V
Quantity
Mantle volume percentage
Section Title
Earth Formation & Structure
Important Facts
- Earth formed from gravitational clumping of dust and particles
- Core made of iron and nickel
- Mantle is 1,800 miles thick
- Continental crust thicker than oceanic crust
- Atmosphere formed by trapped gases
- Water came from icy comets
Key Definitions
Term
Theia
Example
Impact theory of Moon formation
Definition
Wandering planet that collided with Earth, forming the Moon
Term
Core
Example
Generates Earth's magnetic field
Definition
Dense ball of iron and nickel; solid inner core, liquid outer core
Term
Mantle
Example
Asthenosphere is part of upper mantle
Definition
1,800 miles thick, 80% of Earth's volume; lower mantle and upper mantle
Term
Crust
Example
Where we live on Earth's surface
Definition
Solid outer shell; oceanic crust (denser) and continental crust (thicker)
Term
Lithosphere
Example
Broken into about 15 major plates
Definition
Crust plus uppermost mantle; forms tectonic plates
Diagrams To Know
- Earth's layers cross-section
- Structural vs compositional layers
- Moon formation sequence
Common Values
Value
250 million years ago
Symbol
t
Quantity
Pangea existence
Section Title
Continental Drift & Plate Tectonics
Important Facts
- Four evidences: apparent fit, fossils, rocks/mountains, paleoclimate
- Mesosaurus fossil found on separated continents
- Glacial striations in tropical regions
- Mid-oceanic ridges create new crust
- Divergent: plates move apart (ridges, rifts)
- Convergent: plates collide (mountains, volcanoes, trenches)
- Transform: plates slide past (earthquakes)
Key Definitions
Term
Continental Drift
Example
Pangea supercontinent 250 million years ago
Definition
Theory by Alfred Wegener (1915) that continents move atop semi-fluid mantle
Term
Pangea
Example
All continents were joined together
Definition
Supercontinent that existed 250 million years ago before drifting apart
Term
Seafloor Spreading
Example
Mid-Atlantic Ridge
Definition
Magma rises at mid-ocean ridges, creating new crust and pushing plates apart
Term
Plate Tectonics
Example
Three types: divergent, convergent, transform
Definition
Theory explaining earthquakes, volcanoes, and mountain formation through plate movement
Diagrams To Know
- Pangea reconstruction
- Continental drift evidence map
- Three types of plate boundaries
- Seafloor spreading diagram
Common Values
Value
1 to 9
Symbol
R
Quantity
Richter scale range
Section Title
Earthquakes
Important Facts
- Measured on Richter scale (1-9)
- P waves fastest, arrive first
- S waves cannot travel through liquids
- Surface waves most damaging
- Love waves: horizontal motion, destructive to buildings
- Rayleigh waves: vertical and horizontal motion
Key Definitions
Term
Earthquake
Example
Caused by plate movement along faults
Definition
Sudden release of energy in Earth's crust generating seismic waves
Term
Epicenter
Example
Where earthquake effects are usually strongest
Definition
Point on Earth's surface directly above the hypocenter
Term
Hypocenter
Example
Actual source of seismic energy
Definition
Point beneath Earth's surface where earthquake originates (focus)
Term
P Waves
Example
First waves detected by seismographs
Definition
Primary/compressional waves; fastest, travel through solids and liquids
Term
S Waves
Example
Cannot travel through water
Definition
Secondary/shear waves; slower, travel only through solids
Diagrams To Know
- Earthquake epicenter vs hypocenter
- Seismic wave types and motion
- P wave and S wave propagation
Section Title
Volcanoes & Rock Cycle
Important Facts
- Cinder cone: simplest, built from scoria
- Composite: steep slopes, alternating layers
- Shield: gentle slopes, fluid lava flows
- Lava dome: viscous lava, solidifies around vent
- Intrusive igneous: slow cooling, large crystals
- Extrusive igneous: rapid cooling, small crystals
- Rock cycle: any rock can transform to any other type
Key Definitions
Term
Volcano
Example
Four types: cinder cone, composite, shield, lava dome
Definition
Vent in Earth's crust through which molten rock and gases are ejected
Term
Igneous Rocks
Example
Granite (intrusive), Basalt (extrusive)
Definition
Formed from cooling of molten rock (magma/lava)
Term
Sedimentary Rocks
Example
Limestone, Sandstone, Shale
Definition
Formed by deposition and cementation of particles
Term
Metamorphic Rocks
Example
Marble (from limestone), Slate (from shale)
Definition
Formed when rocks undergo high heat and pressure
Diagrams To Know
- Four volcano types comparison
- Rock cycle diagram
- Igneous rock formation process
Section Title
Weathering & Earth Processes
Important Facts
- Physical weathering: no chemical change
- Chemical weathering: creates new substances
- Biological weathering: caused by plants/animals
- Foliated metamorphic: high temperature and pressure
- Non-foliated metamorphic: high temperature, low pressure
Key Definitions
Term
Weathering
Example
Freeze-thaw action, limestone dissolving
Definition
Breaking down of rocks by physical, chemical, or biological means
Term
Erosion
Example
River carrying sediments downstream
Definition
Transport of rock fragments by wind, water, or ice
Term
Deposition
Example
River delta formation
Definition
Dropping of transported sediments in new locations
Term
Compaction
Example
Formation of sedimentary rocks
Definition
Pressing and cementing of accumulated materials into rock
Term
Metamorphism
Example
Limestone becoming marble
Definition
Rock transformation due to heat, pressure, and chemical reactions
Diagrams To Know
- Weathering types comparison
- Erosion and deposition cycle
- Metamorphic rock formation
Reactions Or Equations
Note
Example of chemical weathering
Equation
Limestone + Water → Calcium Carbonate
Conditions
Chemical weathering process
Common Values
Value
78%
Symbol
N₂
Quantity
Atmosphere N₂
Value
21%
Symbol
O₂
Quantity
Atmosphere O₂
Value
97%
Symbol
%
Quantity
Saltwater percentage
Section Title
Earth's Spheres
Important Facts
- Four interconnected Earth systems
- Atmosphere: 78% N₂, 21% O₂, 0.93% Ar, 0.04% CO₂
- 97% of hydrosphere is saltwater
- Biosphere existed for 3.8 billion years
- Goldilocks zone allows liquid water
- Earth's magnetic field protects from radiation
Key Definitions
Term
Lithosphere
Example
Where tectonic plates exist
Definition
Solid outer part of Earth including crust and uppermost mantle
Term
Hydrosphere
Example
Oceans, lakes, rivers, ice, water vapor
Definition
All water on Earth in liquid, gas, and solid forms
Term
Atmosphere
Example
78% Nitrogen, 21% Oxygen
Definition
Layer of gases surrounding Earth held by gravity
Term
Biosphere
Example
Includes all living organisms
Definition
Part of Earth where life exists
Diagrams To Know
- Four Earth spheres interaction
- Atmosphere composition pie chart
- Hydrosphere distribution
Must Remember
- Big Bang occurred 13.7 billion years ago creating universe from singularity
- Solar System is 4.568 billion years old, located in Milky Way galaxy
- Earth has four layers: crust, mantle, outer core, inner core
- Continental Drift Theory: Pangea existed 250 million years ago
- Three plate boundaries: divergent (apart), convergent (together), transform (slide)
- P waves fastest, S waves cannot travel through liquids, surface waves most damaging
- Four volcano types: cinder cone, composite, shield, lava dome
- Rock cycle: igneous → sedimentary → metamorphic (any direction possible)
- Earth's atmosphere: 78% N₂, 21% O₂, 0.93% Ar, 0.04% CO₂
- Four Earth spheres: lithosphere, hydrosphere, atmosphere, biosphere
Last Minute Tips
- Remember the Big Bang timeline: Radiation Era (immediate to 100 sec) then Matter Era (50,000 years onward)
- For earthquake questions: P waves arrive first, S waves cannot go through liquids, surface waves cause most damage
- Continental Drift evidence: puzzle fit, fossils, rock correlation, paleoclimate - memorize all four
- Plate boundaries: Divergent = rifts/ridges, Convergent = mountains/volcanoes/trenches, Transform = earthquakes
- Rock identification: Igneous from cooling, Sedimentary from layers/fossils, Metamorphic from heat/pressure changes
Comparison Tables
Rows
Values
- High-energy particles and radiation
- Matter becomes dominant
Property
Dominance
Values
- Formation of fundamental forces
- Formation of elements and structures
Property
Key Events
Values
- Extremely hot (10^40 K to 10^9 K)
- Cooler (3000 K and below)
Property
Temperature
Values
- Immediate to 100 seconds
- 50,000 years to present
Property
Duration
Columns
- Aspect
- Radiation Era
- Matter Era
Table Title
Radiation Era vs Matter Era
Rows
Values
- Rocky (silicates, iron, nickel)
- Gaseous (hydrogen, helium, ices)
Property
Composition
Values
- Smaller
- Larger (gas giants)
Property
Size
Values
- Thin or none
- Thick atmosphere
Property
Atmosphere
Values
- Higher density
- Lower density
Property
Density
Values
- Slower rotation
- Faster rotation
Property
Rotation
Columns
- Property
- Inner Planets
- Outer Planets
Table Title
Inner vs Outer Planets
Rows
Values
- Cooling of molten rock
- Granite, Basalt
- Intrusive: large crystals; Extrusive: small crystals
Property
Igneous
Values
- Deposition and cementation
- Limestone, Sandstone
- Clastic, Chemical, or Organic origin
Property
Sedimentary
Values
- Heat and pressure transformation
- Marble, Slate
- Foliated or Non-foliated structure
Property
Metamorphic
Columns
- Rock Type
- Formation Process
- Examples
- Key Features
Table Title
Rock Types Comparison
Rows
Values
- Fastest
- Solids and liquids
- Compressional
- Low
Property
P Waves
Values
- Medium
- Solids only
- Horizontal/sideways
- Medium
Property
S Waves
Values
- Slow
- Surface
- Horizontal
- High
Property
Love Waves
Values
- Slowest
- Surface
- Vertical and horizontal
- Highest
Property
Rayleigh Waves
Columns
- Wave Type
- Speed
- Medium
- Motion
- Damage Level
Table Title
Seismic Waves Comparison
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