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CIE IGCSE Physics Chapter 6: Space Physics 思维导图 - Coggle Diagram
CIE IGCSE Physics Chapter 6: Space Physics 思维导图
1. Earth and the Solar System
1.1 Earth
Rotation
:
Axis: Imaginary line through N & S poles
Tilt: 23.5°
Direction: West to East
Duration: 24 hours (day & night)
Orbit
:
Around Sun
Shape: Ellipse
Duration: 365 days (year)
Seasons: Due to axis tilt & orbit
1.2 Moon
Orbit
:
Around Earth
Duration: 28 days (month)
Phases: Changes in illuminated side
1.3 Solar System
Components
:
Sun: Central star
Planets: 8 (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune)
Minor Planets: Dwarf planets (e.g., Pluto), asteroids
Moons: Orbit planets
Other: Comets, natural satellites
Formation
:
4.6 billion years ago from gas & dust cloud
1.4 Orbital Mechanics
Average Orbital Speed
:
Formula: $v = \frac{2\pi r}{T}$
Example: Earth around Sun = 29.8 km/s
Elliptical Orbits
:
Planets closer/farther from Sun at different times
Perihelion & Aphelion
Eccentricity: Degree of oval-shape
Energy
:
Kinetic & Potential Energy vary with distance from Sun
Total Energy: Constant (conservation of energy)
2. Stars and the Universe
2.1 The Sun
Type
: Medium-sized star
Composition
: Mostly hydrogen & helium
Energy Source
: Nuclear fusion
Hydrogen to helium
High temperature & pressure in core
2.2 Galaxies
Definition
: Collections of stars, gas, dust held by gravity
Examples
: Milky Way (spiral shape)
Number
: Billions of galaxies with billions of stars each
2.3 Star Life Cycle
Birth
: From gas & dust clouds (nebulae)
Main Sequence
: Hydrogen fusion
Evolution
:
Red giants/supergiants
White dwarfs, neutron stars, black holes (end states)
2.4 Universe Expansion
Evidence
: Redshift in light from distant galaxies
Theories
:
Big Bang: Universe began as hot, dense point 13.8 billion years ago
Cosmic Microwave Background Radiation (CMBR): Remnant of early Universe
Hubble Constant (H₀)
:
Expansion rate: 2.2 × 10⁻¹⁸ per second
Estimated Universe age: 14 billion years