The Inner Planets Are Made Mostly of Rock and Metal

question 2

Multiple Choice

The inner planets are made mostly of rock and metal because:

• A) lighter materials cannot orbit the Sun; they would fall in immediately
• B) the Sun is made mostly of rock and metal and the inner planets are closest to the Sun
• C) it was so hot where the inner planets formed that the lighter materials evaporated
• D) Jupiter's large gravity immediately attracted all the lighter materials, and so there were few light atoms left by the time the inner planets were ready to form
• E) this is an unsolved problem in astronomy