Solar System Formation
What was the solar system formed from?
A rotating cloud of gas and dust called the solar nebula.
What are the two main categories of planets in our solar system?
Terrestrial and Jovian planets.
According to Kepler's First Law, what shape are planetary orbits?
Ellipses, with the Sun at one focus.
What is the rigid outer mechanical layer of Earth called?
lithosphere
What do scientists study to learn about Earth's deep interior?
Seismic waves from earthquakes.
Name one major source of heat inside Earth.
Leftover heat from early impacts or heat from radioactive decay.
What process allowed small pieces of material to combine into larger bodies and eventually planets?
Accretion
Where are dense, rocky planets most likely to form?
Near the central star.
When does a planet move fastest in its orbit?
When it is closest to the Sun.
Which mechanical layer includes Earth's crust?
lithosphere
Which type of seismic wave cannot travel through liquids?
S waves.
What process transfers heat through the mantle?
What process transfers heat through the mantle?
Answer: Convection.
What event may have triggered the collapse of the original solar nebula?
A nearby supernova.
What factor has the greatest influence on how long a star lives?
Its mass.
What two measurements are related by Kepler's Third Law?
Orbital period and average distance from the Sun.
Which layer is softer and more easily deformed: the lithosphere or asthenosphere?
asthenosphere
How do the coils of a stretched spring move when a P wave passes through?
They compress and spread out parallel to the wave’s travel direction.
Does mantle convection involve the movement of solid rock or liquid water?
Very slow movement and deformation of solid rock.
What began in the central protostar when it became hot and dense enough?
Nuclear fusion
Where did many of the heavy elements found on Earth originate?
Supernova explosions.
A planet has a semimajor axis of 4 AU. Using P² = a³, what is its orbital period?
8 years. P² = 4³ = 64, so P = 8 years.
What three properties generally increase with depth inside Earth?
Temperature, pressure, and density.
How do the coils move when an S wave passes through a stretched spring?
Sideways, perpendicular to the wave’s travel direction.
How is mantle convection related to Earth's surface?
It is associated with the movement of tectonic plates.
Put these stages in order: stellar wind clears gas, planetesimals accrete, nebula collapses, nuclear fusion begins.
Nebula collapses → nuclear fusion begins → planetesimals accrete → stellar wind clears leftover gas.
Why are the inner planets mostly rocky while the outer planets are largely gaseous?
The inner nebula was hotter, favoring rocky materials; cooler outer regions allowed gas- and ice-rich planets to develop.
What technique uses light to identify the composition of stars and planets?
Spectroscopy; astronomers analyze the light and its spectral features.
Where are Earth's tectonic plates located?
In the rigid lithosphere, extending from the surface to approximately 100 km deep in the textbook model.
How can scientists locate an earthquake's epicenter?
By comparing P- and S-wave arrival times at at least three seismic stations.
Explain the two sources of Earth's internal heat and how that heat relates to tectonic plate movement.
Early impact heat and radioactive decay supply internal heat. Slow mantle convection transfers heat and is associated with tectonic plate motion.