What is the nebular hypothesis?

• A theory that describes the formation of the solar system from a spinning cloud of dust and gas.

• A theory that explains the formation of stars from black holes.

• A theory that describes the collision of two galaxies.

• A theory that explains the expansion of the universe.

Why are the inner (terrestrial) planets of the solar system rocky?

• Because they formed in high-temperature zones allowing only metals and silicate minerals to condense.

• Because they are closer to the asteroid belt.

• Because they have stronger gravitational pulls.

• Because they are closer to the Kuiper belt.

What is the primary composition of Jupiter and Saturn?

• Hydrogen and helium gas.

• Methane ices and water.

• Silicate minerals and metals.

• Carbon dioxide and ammonia.

What caused the formation of the asteroid belt between Mars and Jupiter?

• Jupiter’s massive gravity causing destructive collisions.

• The collision of two large planets.

• The gravitational pull of the Sun.

• The presence of a large gas giant planet.

Why was Pluto reclassified as a dwarf planet by the IAU?

• It did not clear its orbit of other planetesimals.

• It is not massive enough to create a fusion.

• It is not rounded by its own gravitational forces.

• It is located in the Kuiper belt.