Structures of the Universe
Q: What is a galaxy?
A: A large collection of stars, gas, and dust held together by gravity
Q: What is the main source of energy in stars?
A: Nuclear fusion
Q: What is the celestial matter that allows a star to form?
A: Nebula
Q: What is a light-year?
A: The distance light travels in one year
Q: What happened first in the Big Bang?
A: Rapid expansion
Q: What is a solar system?
A: A star and the objects that orbit it
Q: What two forces balance in a star?
A: Gravity and pressure from fusion
Q: What forms first when a star begins to develop?
A: Protostar
Q: What is parallax?
A: The apparent movement of a star when viewed from different positions
Q: Name key stages in the Big Bang
A: 1. Rapid Expansion, 2. Cooling, 3. Formation of Particles --> Atoms, 4. Formation of Stars and Galaxies
Q: What is a nebula?
A: A cloud of gas and dust where stars form
Q: What happens if gravity is stronger than fusion?
A: The star collapses into a supernova or a neutron star
Q: What does a small star become before it dies?
A: Red giant
Q: What are standard candles used for?
A: Measuring distances in deep space
Q: What does redshift show?
A: The universe is expanding
Q: What is a black hole?
A: An object with gravity so strong that not even light can escape
Q: What happens when fusion is stronger than gravity?
A: The star expands
Q: What is the explosion of a large star called?
A: Supernova
Q: What is magnitude?
A: Measure of a celestial object's brightness, where lower or more negative numbers indicate brighter objects.
Q: What is cosmic microwave background radiation (CMB)?
A: Leftover heat/radiation from the Big Bang ("afterglow" of the Big Bang)
Q: What is a star?
A: A massive ball of hot gas that produces energy through fusion
Q:What is a neutron star?
A:A neutron star is the incredibly dense, city-sized remnant core left behind after a massive star explodes as a supernova
Q: Name two possible outcomes after a supernova
A: Neutron star or black hole
Q: What is the difference between apparent and absolute magnitude?
A: Apparent = how bright it looks from Earth; Absolute = actual brightness if object is 10pc from Earth (intrinsic brightness)
Q: Name the 3 key pieces of evidence supporting the Big Bang
A: Redshift, CMB, or abundance of hydrogen and helium