Chapter 14 Formation of the Solar System

Which of the following is NOT a characteristic that worlds in our solar system have in common:

a. that the planets all revolve around the Sun in the same direction b. that most of the planets spin in the same direction that they revolve c. that many of the larger moons go around their planets in the same direction d. that the planets' orbits lie in roughly the same plane Correct Response e. that all the planets have solid surfaces on which we can see impact craters

Which of the following pieces of observational evidence does our modern "solar nebula" theory of the formation of the solar system NOT explain directly?

a. the fact that all the planets revolve around the equator of the Sun in the same direction b. the difference in the composition of the terrestrial and jovian planets c. the ages of the oldest rocks on Earth, the Moon, and meteorites Correct Response d. the plane of the orbit of Pluto

When the solar system was forming, the building blocks from which the protoplanets gathered together were the:

planetesimals (a few km to tens of km wide)

How do astronomers know that the age of the solar system is about 4.5 billion years old?

radioactive dating of the primitive meteorites indicates they have age (since they are left-over building blocks of the solar system)

Astronomers now believe that the differences in composition among the planets reflect what characteristic in the early solar system

temperature

The reason that worlds like the Earth are differentiated is that

the continuing impacts on a growing protoplanet eventually melted the entire body

Astronomers call the vast, rotating cloud of vapor and dust from which the solar system formed:

the solar nebula

A key difference between the protoplanets that formed in the outer solar system and those that formed in the inner solar system was that

those in the outer solar system were in a place where ice, not just rock, condensed and thus could grow larger

Among solid worlds, which type of world is most likely to have significant geological activity?

those that are the largest (and retain heat the best)