Formation of the Solar System
This theory states that the Solar System formed from a rotating cloud of gas and dust about 4.6 billion years ago.
What is the Nebular Theory?
These four planets are known as the inner planets because they are located closest to the Sun.
What are Mercury, Venus, Earth, and Mars?
These four planets are known as the outer planets because they orbit the Sun beyond the asteroid belt.
What are Jupiter, Saturn, Uranus, and Neptune?
Asteroids are found primarily in the belt between these two planets.
What are Mars and Jupiter?
This is how many dwarf planets there currently are in our solar system, according to the International Astronomical Union (IAU).
What is five?
As gravity caused the solar nebula to collapse, most of the material concentrated at the center to form this object.
Protosun or Sun
This characteristic is shared by all inner planets and distinguishes them from the gas giants.
What are rocky, solid surfaces?
This outer planet is the largest in the Solar System and has a prominent Great Red Spot.
What is Jupiter?
This key compositional difference distinguishes most comets from most asteroids.
What is that comets contain significant amounts of ice, while asteroids are primarily rocky or metallic?
This former planet was reclassified as a dwarf planet in 2006 by the International Astronomical Union.
What is Pluto?
These small, solid particles formed in the early solar nebula and later collided and stuck together to build planets.
What are planetesimals?
This inner planet has the highest average surface temperature due to a runaway greenhouse effect.
What is Venus?
These two outer planets are classified as ice giants.
What are Uranus and Neptune?
This component of a comet always points away from the Sun due to the solar wind.
What is the ion (gas) tail?
This dwarf planet, located in the asteroid belt, is the largest object in that region.
What is Ceres?
This process describes how dust and rock in the solar nebula gradually clumped together through collisions to form larger bodies.
What is accretion?
This planet has the largest iron core relative to its size of any planet in the Solar System.
What is Mercury?
This feature is found on all four outer planets and is most dramatically visible around Saturn.
What are planetary rings?
These are the three types of asteroids based on composition.
What are C-type, S-type, and M-type?
The discovery of this trans-Neptunian object, comparable in size to Pluto, directly led to the 2006 IAU redefinition of “planet.”
What is Eris?
This explains why terrestrial planets are rocky while gas giants are composed mostly of hydrogen and helium.
What is a result of lighter gases/elements condensing at higher temperatures closer to the Sun? (aka "frost line")
Compared to the outer planets, the inner planets have relatively few of these because the Sun’s heat and solar wind cleared them away early in Solar System history.
What are moons (natural satellites)?
Jupiter and Saturn are classified differently from Uranus and Neptune because they are composed mostly of these two elements.
Hydrogen and helium
This distant, spherical region is thought to be the source of long-period comets, while short-period comets are believed to originate primarily from this flattened region beyond Neptune.
What are the Oort Cloud and the Kuiper Belt?
This criterion distinguishes dwarf planets from full-fledged planets despite both being in hydrostatic equilibrium.
What is the failure to clear their orbital neighborhood?