The Solar System Flashcards
Lectures 1-3
Out of the 13 planetary bodies, how many are planets?
8
Out of the 13 planetary bodies, how many are dwarf planets?
5
What are the three factors that define a planet by the IAU?
- It must orbit the sun
- It must be large enough to take a spherical shape.
- It must have cleared it’s orbit of other planets
What are the four factors that define a dwarf planet by the IAU?
- It must orbit the sun
- It must be large enough to take on a spherical shape
- It has not cleared it’s orbit
- It is not a satellite
What are the two types of planets?
Terrestrial and Jovian
Which are the Terrestrial planets?
Mercury, Venus, Earth, Mars
Which are the Jovian planets?
Jupiter, Saturn, Uranus, Neptune
What three factors would define a terrestrial planet?
- High Density
- Solid Rocky Surface
- Metallic core
What factors would describe a Jovian planet?
- Low Density
- Gaseous
- Not defined surface
List the five official dwarf planets
- Ceres
- Pluto
- Eris
- Haumea
- Makemake
What are Kepler’s three laws?
- Planets orbit the sun in an ellipse with the Sun and the centre
- The line between the planet and the sun sweeps out an area at a constant rate
- The period of the orbit of a planet is proportional to a3/2 where a is the semi-major axis of the ellipse.
What is De Buffon’s Passing Star Model (Catastrophic Model)?
The theory that planets were formed by the sun pulling materials from another star close to it.
What are 3 examples of problems of De Buffon’s Passing Star Model?
- The material pulled from the sun would be very hot and unlikely to form planets.
- Circular orbits would be unlikely
- Does not explain varying properties of different planets
What is the Evolutionary model?
The sun and the planets are formed from a nebula of gas and dust
What is stage 1 of the evolutionary model/the solar nebula hypothesis?
The cloud of Gas and Dust
What happens at stage 1 of the evolutionary model/the solar nebula hypothesis (The cloud of gas and dust)
The sun and the planets are formed at the same time from rotating cloud of gas.
What is stage 2 of the evolutionary model/the solar nebula hypothesis?
Disc rotation
What are the 3 steps of stage in the evolutionary model/the solar nebula hypothesis (Disc Rotation)?
- As the clouds rotated, it became smaller.
- Gravity causes a concentration at the centre of the disc which became the sun.
- Further from the centre, dust and molecules of gas created other bodies by a process of accretion.
What is stage 3 of the evolutionary model/the solar nebula hypothesis?
The formation of planetesimals
What happens during stage 3 of the evolutionary model/the solar nebula hypothesis? (the formation of planetismals) (3 factors)
- The accretion bodies formed in Stage 3 are too small for gravity to be effective
- Clumps of matter acted as condensation nuclei
- Through electrostatic forces, the bodies started to coalesce and grow.
What is stage 4 of the evolutionary model/the solar nebula hypothesis?
The formation of protoplanets
What happens during stage 4 of the evolutionary model/the solar nebula hypothesis? (the formation of protoplanets) (2 points)
- At this point, clumps have coalesced into larger bodies (about 100km in diameter)
- Due to their size, they have a large gravitional attraction and collect other bodies effectively until they become planets.
What are the 2 successes of the evolutionary model/the solar nebula hypothesis?
- Explains the disc shape of a solar system
- Explain why everything rotates the same way
What two elements can small planets not capture?
Hydrogen and helium
How many times the mass of the earth must a planet be before it captures gas?
15x the mass of the earth
What is stage 1 of the formation of the planet?
Accretion and Differentiation
What is accretion and differentiation?
- Accrection is when it pulls part of matter to form protoplanets.
- Differentation is when gravity pulls heavier elements to the planet’s core
What is stage 2 of the formation of the planet?
Period of intense bombardment
What happens at stage 2 of the formation of the planet? (The period of intense bombardment)
The planet pulls remaining debris and creates cratering.
What is stage 3 of the formation of the planet?
Flooding by Lava and Water
What is stage 4 of the formation of the planet?
Slow evolution
What 2 points are made for the reason of excess debris being cleared?
- Solar winds and radiation
- Gravity removed larger bodies
How old is the solar system?
4.6 x 10-9 years old
How old is the universe?
14 x 10-9 years old
How do we know about the interior of the Earth?
Seismac waves
What are the two types of seismac waves?
Shear and Pressure
What are the three stages of the interior of the Earth?
- The Crust
- The Mantle
- The Core
What is the depth of the crust of the earth?
10km
What is the range between the mantle and the core?
60km-2800km
What is the range of the outer part of the core and how dense is it? (Solid or Liquid?)
2800-5200km, liquid
What is the range of the inner part of the core and how dense is it? (Solid or Liquid?)
5200-6300km, solid
What is the temperature of the Earth’s core?
Around 5000 degrees.
What are the three requirements for a magnetic field (dynamo effect)
- Electrically conduncting liquid core
- Convection currents in the core
- Fast rate of rotation
What is the Magnetosphere?
Region of space that is controlled by the magnetic field and not solar winds.
What is the point of the Magnetosphere?
Keeps solar wind away from surface
What region of the Earth is the lithosphere located?
The top of the mantle