ASTRONOMY Flashcards
(28 cards)
What is Earth’s address in the universe?
Earth > Solar System > Milky Way > Local Group > Universe
What type of galaxy is the Milky Way?
Spiral galaxy; contains stars, planets, gas, dust
What is the Big Bang Theory?
Universe began from a hot, dense point ~13.8 billion years ago
What evidence supports the Big Bang Theory?
- Redshift
- CMB radiation
What is Cosmic Microwave Background (CMB)?
Radiation leftover from Big Bang
What does redshift indicate?
Light stretches as galaxies move away; shows universe expanding
What is spectroscopy?
Analyzing light spectrum to find composition
What are absorption lines?
Specific elements absorb specific wavelengths
What is the electromagnetic spectrum?
All types of light; most received: visible & infrared
What is blackbody radiation?
Hot objects emit light; hotter = shorter wavelengths
What does Wein’s Law state?
Peak wavelength inversely related to temperature
What is luminosity?
Brightness of a star
What is a nebula?
Gas cloud that forms stars
What initiates star formation?
Gravity compresses gas → nuclear fusion starts
What are the forces involved in star formation?
- Gravity pulls in
- Fusion pushes out
What are the types of stars based on mass?
- Low Mass: Long life; ends as white dwarf
- Medium Mass: Like Sun; red giant → planetary nebula → white dwarf
- High Mass: Short life; supernova → neutron star or black hole
How does mass affect fusion in stars?
Bigger stars = faster fusion = shorter life
Which stars make elements heavier than iron?
Only high-mass stars
What are the types of eclipses?
- Solar: Moon blocks Sun
- Lunar: Earth blocks sunlight from Moon
What is the celestial sphere?
Imaginary sky dome used for tracking stars
What are the two models of the solar system?
- Geocentric: Earth-centered (wrong)
- Heliocentric: Sun-centered (correct)
What is retrograde motion?
Apparent backward motion of planets
Who proposed the heliocentric model?
Copernicus
What did Brahe contribute to astronomy?
Collected precise planetary data
