Questions & Answers
Lesson 1: The Solar System - ANSWERS...
Which is the correct sequence of planets, based on increasing average radius of their orbits? -
ANSWERSClosest to Sun
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
Pluto
Farthest from Sun
The inner planets __________. - ANSWERSNONE of these:
-have about the same size as the outer planets
-all have several moons
-have about the same composition as the outer planets
,-all have orbiting systems of rings
The outer planets are hydrogen-helium mixtures, larger than the inner planets, and have rings
and moons. They contrast with the inner planets in each of these aspects.
Which statement is true for the outer planets of our solar system? - ANSWERSThey are largely
made of hydrogen and helium.
NOT:
-they produce enough internal energy to glow like the Sun
-they have solid surfaces just below a layer of clouds
-they lack systems of rings.
The giant outer planets are not large enough to sustain nuclear fusion like stars, but they are
made of similar materials - hydrogen and helium. They have no solid surfaces and they
commonly have rings.
Water ice is __________. - ANSWERSmost abundant on the moons of the outer planets
Water ice is stable and common on the moons of the outer planets and into the Kuiper belt. It is
unstable in the near vacuum of the inner solar system because the temperature is too high.
What sets the composition of the moons of the outer planets apart from the inner planets? -
ANSWERSThe moons of the outer planets generally have lower densities.
The moons of the outer planets are too small to retain atmospheres of hydrogen and helium
and are dominantly water ice rather than nitrogen ice, which is only stable in the far outer
reaches of the solar system.
, Which objects have orbits that take them the farthest from the Sun in our solar system? -
ANSWERSComets
Some comets have orbital periods of hundreds of thousands of years. The group of comets that
occupies the outermost limits of the solar system is called the Oort Cloud.
Which of the following objects is most like Earth in size and composition? - ANSWERSVenus
Venus is nearly the same diameter and composition to Earth. Neptune is large and
compositionally very different, and the others (Mercury, Ida, & Mars) are rocky like Earth, but
significantly smaller.
What is a major difference between planets and stars? - ANSWERS-Planets are much smaller in
diameter than the stars around which they revolve.
-Planets do not generate energy through nuclear fusion.
Planets have rings and systems of orbiting moons and some planets (the outer planets) lack
solid surfaces.
What are the major differences between a moon and a planet? - ANSWERS-Planets revolve
around the Sun.
-Moons revolve around a Sun-orbiting planet.
A few moons are actually bigger than Pluto and Mercury. By definition, moons (natural
satellites) don't orbit around the Sun but instead revolve around another planetary body. Some
asteroids even have moons.
Which of the following are the characteristics of the asteroid belt? - ANSWERS-The asteroids
mark the transition from the rocky terrestrial planets to the outer planets.