Solar System and the Sun Flashcards
What is the solar nebula?
A collection of gas and dust from which the Solar System formed.
What is a planetesimal?
A body of accreted gas and dust.
What is accretion?
The process of growth by the gradual build-up of matter.
What started the solar nebula collapse?
A trigger event such as a supernova explosion.
Why do scientists believe that the solar nebula is a remnant of an earlier supernova explosion of a high mass star?
The gas and dust in the solar nebula included elements besides hydrogen and helium.
How does the motion of planets and asteroids support the nebular hypothesis?
The orbits of planets and asteroids are counterclockwise in a relatively flat plane.
What is the first step to the formation of planets?
Material outside the protostar begins to clump and stick together by electrostatic attraction.
What is the second step that changes planetesimals into planets?
Larger particles form by collisions and gravitational attraction.
What two properties define a planet?
Planets have a spherical shape and have gravitationally cleared the area around their orbit.
What two characteristics got Pluto demoted from planet to dwarf planet status?
Pluto is too small and its orbit is highly irregular (too elliptical)
What are two properties of the inner planets?
They are made from mostly silicates and metals (rocky planets). They are smaller than the outer planets.
What are properties of the outer planets?
They are made from small hydrogen compounds in the gas state. They are large, have many moons and have ring systems.
Which planets are considered inner planets?
Mercury, Venus, Earth and Mars
Which planets are considered outer planets?
Jupiter, Saturn, Uranus, and Neptune
What is the Kuiper Belt
An area of the solar system beyond the orbit of Neptune believed to contain dwarf planets, small rocky bodies, and some comets.
What is the Oort Cloud?
An area at the outer part of the solar system from which many long-period comets originate
What is a comet?
A ball of ices and dust that orbits the Sun
How does the Sun generate energy?
Nuclear fusion of hydrogen into helium in its core
What is the layer of the Sun outside its core? How does energy move through this layer?
The radiative zone is outside the core. Energy slowly radiates (plasma absorbs and emits photons of energy) from the core towards the convective zone.
What is the outer layer of the Sun’s interior? How does energy move through this layer?
The convective zone is outside the radiative zone. Energy moves through the convective zone by convection (warm plasma rises and cool plasma sinks)
What layer is considered the Sun’s surface?
The photosphere
What layer of the Sun’s atmosphere is outside the photosphere?
The chromosphere
What layer is considered the outer layer of the Sun’s atmosphere?
The corona
What are features associated with the Sun’s magnetic field?
Sunspots, prominences, solar flares, and streamers
