Chapter 7

If you were to take a large sample of the four giant planets, the most common element you would find in them is:

Hydrogen

A planet in our solar system whose composition resembles that of our Sun is:

Jupiter

Which of the following is NOT a terrestrial planet?;

Jupiter

The smaller objects in the solar system made of rock and metal (most of which orbit between Jupiter and Mars) are called:

Asteroids

In general, the further planets are from the Sun, the cooler they are. What other factor can have a significant influence on a planet's surface temperature?

its atmosphere (whether it has one and how thick it is)

All the planets (without exception);

revolve around the Sun in the same direction

What is the most important reason that astronomers have learned more about our planetary system in the last 30-40 years than all of history before then

we have been able to send spacecraft to gather information about planets and moons up close

In a bad late-night science fiction film, a villain is using a large collection of rare radioactive atoms as energy for a weapon to threaten the good guys. The atoms have a half-life of 1 hour. The villain has 4 kilograms of the radioactive material now, and he needs a minimum of 1 kg. for his weapon to work. After how much time will the weapon no longer be a threat?

just a little after 2 hrs

In the four terrestrial planets, the densest, heaviest materials are at the center and not evenly distributed throughout the planet. Scientists interpret this observation to mean that:

the four terrestrial planets must once have been hot enough to be molten (like a liquid)

Which of the following characteristics do all four terrestrial planets have in common?

they all have solid surfaces with signs of geological activity on them