Space Objects and Solar System

Astronomical Objects

• Planet orbits a star, is nearly round, and has cleared its orbital path
• Dwarf Planet resembles a planet but hasn't cleared its orbit
• Moon is a natural satellite orbiting a planet
• Asteroid is a small, rocky object mainly found between Mars and Jupiter
• Comet is an icy body with a glowing coma and tail when near the Sun
• Meteoroid is a space rock fragment
• Meteor is the streak of light produced as a meteoroid burns in Earth's atmosphere
• Meteorite is a meteoroid that lands on Earth

Solar System Regions

• Asteroid Belt is located between Mars and Jupiter
• Kuiper Belt is a flat, icy disk beyond Neptune
• Oort Cloud is a spherical shell far beyond the planets and is the source of long-period comets
• Trans-Neptunian Objects orbit beyond Neptune

Earth Movements

• Rotation refers to a planet spinning on its axis, causing day and night
• Revolution is orbiting the Sun, causing seasons and yearly cycles
• Earth's Tilt is the primary cause of seasonal changes

Moon Phases & Eclipses

• Lunar Eclipse occurs when the Moon is in Earth's shadow
• Solar Eclipse happens when the Moon blocks sunlight from reaching Earth
• Full Moon is when the Moon is fully illuminated
• Phases of the Moon result from the Moon's orbit around Earth

Stars & Their Life Cycle

• Nuclear Fusion is the energy source of stars, converting hydrogen into helium
• Star Evolution (for low mass stars) follows this sequence: Main sequence -> Red giant -> Planetary nebula -> White dwarf
• High Mass stars end their life cycle as Supernova -> Neutron star or Black hole
• Spectral Types of stars are classified as O (hottest) -> B -> A -> F -> G -> K -> M (coolest)
• H-R Diagram graphs star brightness vs temperature and it is used to trace star evolution

The Universe

• Big Bang Theory states the universe began from an extremely hot, dense state
• CMB Radiation serves as evidence of the Big Bang
• Dark Matter explains extra mass observed in galaxies
• Dark Energy accounts for the acceleration in the universe's expansion
• Redshift indicates light is stretched, and object is moving away, implying the universe is expanding
• Blueshift indicates light is compressed, and object is approaching
• Doppler Effect is the change in wavelength due to motion

Black Holes

• Black Hole is a region of intense gravity from which nothing, including light, can escape
• Event Horizon is the boundary around a black hole beyond which no escape is possible
• Spaghettification is the stretching of objects due to extreme gravity near a black hole
• Time Dilation is the slowing of time in strong gravitational fields

Multiple Choice Concepts

• Planets can be either rocky (terrestrial) or gaseous (Jovian)
• Revolution means orbiting a star, while rotation means spinning on an axis
• Redshift proves the universe is expanding
• Coolest stars belong to spectral class M
• Venus is hotter than Mercury due to the greenhouse effect

Short Answer Tips

• Dark Matter explains the fast star speeds observed in galaxies
• CMB radiation supports the theory of an early, hot universe during the Big Bang
• H-R Diagram classifies stars and their life stages
• Ethical Concern involves avoiding contamination during space exploration