Unit 3: Planetary & Stellar Science Flashcards (Complete)

Planetary Science Flashcards

Q: What defines a planet according to the IAU?
A: A celestial body that (1) orbits the Sun, (2) has enough mass for a nearly round shape, and (3) has cleared its orbit of other debris.

Q: What is the main difference between terrestrial and Jovian planets?
A: Terrestrial planets are rocky (like Earth), while Jovian planets are gas giants (like Jupiter).

Q: Which planet has the highest surface temperature due to the greenhouse effect?
A: Venus.

Q: What is the Kuiper Belt?
A: A region beyond Neptune with small icy bodies, including Pluto.

Q: What defines the habitable zone of a star system?
A: The region around a star where liquid water can exist on a planet's surface.

Q: Which planet is tilted on its side, causing extreme seasons?
A: Uranus.

Q: What is retrograde motion?
A: The apparent backward movement of a planet as Earth overtakes it in orbit.

Q: What is the significance of Kepler’s Laws?
A: They describe how planets orbit the Sun (elliptically, sweeping equal areas in equal time, and orbital period related to distance).

Q: What is the Titius-Bode Law?
A: A pattern suggesting regular spacing of planets from the Sun.

Q: What is an exoplanet?
A: A planet orbiting a star outside our solar system.

Q: How do we detect exoplanets?
A: Transit method (dimming of star) and radial velocity (wobble in star's motion).

Stellar Science Flashcards

Q: What is the main factor that determines a star’s lifecycle?
A: Its mass.

Q: What is the life cycle of a low-mass star like the Sun?
A: Nebula → Protostar → Main Sequence → Red Giant → Planetary Nebula → White Dwarf.

Q: What is a supernova?
A: An explosive death of a massive star, leading to a neutron star or black hole.

Q: What defines the main sequence phase?
A: Hydrogen fusion into helium.

Q: What is the nuclear fusion process in stars?
A: Hydrogen atoms fuse into helium, releasing energy.

Q: What is a neutron star?
A: A dense core left after a supernova, made mostly of neutrons.

Q: What is the Doppler effect in astronomy?
A: A shift in spectral lines due to motion (redshift = away, blueshift = toward).

Q: What was Galileo's contribution to stellar observation?
A: He used telescopes to observe celestial bodies, supporting the heliocentric model.

Q: What was Tycho Brahe’s role in stellar science?
A: Provided precise planetary data before telescopes.

Q: What is spectroscopy?
A: The study of how stars absorb and emit light, revealing their composition.

Q: What is the Hertzsprung-Russell (H-R) Diagram?
A: A graph that classifies stars by brightness and temperature.

Q: Who introduced computer modeling of stars?
A: M. Schwarzschild and Fred Hoyle.

Q: What marks the beginning of modern cosmology?
A: Einstein’s General Theory of Relativity (1915).

ICQ questions

1. What model did Copernicus propose?
   
   

   • The Heliocentric Model (Sun-centered).
     
     

2. What observation by Galileo supported the heliocentric model?
   
   

   • Moons orbiting Jupiter.
     
     

3. What defines the main sequence in a star's life?
   
   

   • The phase where hydrogen is fused into helium.
     
     

4. What type of star ends its life as a white dwarf?
   
   

   • Low-mass stars like the Sun.
     
     

5. How does mass affect a star’s evolution?
   
   

   • Higher mass leads to shorter lifespans and explosive ends (supernovae).
     
     

Summary for Long Answer (Planetary & Stellar Science)

Planetary Science Summary:
The evolution of planetary models began with the geocentric theory (Earth-centered), which was challenged by observations such as retrograde motion and Galileo’s discovery of Jupiter's moons. The heliocentric model (Sun-centered) gained acceptance through the work of Copernicus, Kepler, and Newton. The study of exoplanets has advanced using techniques like the transit and radial velocity methods. Understanding planetary systems helps locate habitable zones where liquid water may exist, a key factor in the search for life.

Key Planetary Terms:

• Geocentric Model: The outdated belief that Earth is at the center of the universe and all celestial bodies orbit around it.
  
  

• Heliocentric Model: The correct model of the solar system where the Sun is at the center, and planets orbit around it.
  
  

• Retrograde Motion: The apparent backward motion of a planet when Earth passes it in its orbit.
  
  

• Exoplanets: Planets that orbit stars outside of our solar system.
  
  

• Habitable Zone: The region around a star where temperatures allow liquid water to exist on a planet's surface, crucial for life.
  
  

Stellar Science Summary:
Stars evolve based on their mass. Low-mass stars like the Sun follow a stable life cycle ending as white dwarfs, while massive stars end as neutron stars or black holes after supernovae. The H-R Diagram is a vital tool to categorize stars by luminosity and temperature. Spectroscopy helps determine the chemical composition of stars, while the Doppler effect provides information about stellar motion. Modern cosmology builds upon Einstein’s relativity to understand large-scale universe dynamics.

Key Stellar Terms:

• Main Sequence: The stable phase in a star's life where it fuses hydrogen into helium in its core.
  
  

• Hertzsprung-Russell (H-R) Diagram: A graph that shows the relationship between a star’s luminosity (brightness) and its temperature (color).
  
  

• Spectroscopy: A technique that analyzes the light from stars to determine their chemical composition.
  
  

• Doppler Effect: The change in frequency or wavelength of light from an object moving toward or away from an observer; used to measure star/galaxy motion.
  
  

• Supernova: A massive explosion marking the end of a large star’s life, often creating neutron stars or black holes.