The Oort Cloud is thought to be:
A) the cloud of gas and dust from which our solar system formed.
B) a cloud of debris that occasionally encounters the Earth, causing a meteor shower.
C) the spherical cloud of comets and some larger icy bodies surrounding the outer solar system.
D) a cloud of asteroids moving between the orbits of Mars and Jupiter.
E) the material in the ecliptic plane that creates the zodiacal light.
Question 2Consider the following statement: Rocky asteroids are found primarily in the asteroid belt and Kuiper belt while icy comets are found primarily in the Oort cloud. What's wrong with this statement?
A) Asteroids are not made of rock.
B) Comets are not icy.
C) The Kuiper belt contains icy comets, not rocky asteroids.
D) The Oort cloud has nothing to do with comets.
E) The statement is accurate as written.
Question 3When was Pluto discovered?
A) about 30 years ago
B) about 80 years ago
C) about 200 years ago
D) about 2000 years ago
E) in ancient history
Question 4Scientists today do not accept the Ptolemaic model because
A) it is ancient history.
B) it was too complicated, compared to Copernicus' heliocentric model.
C) it has been shown that Ptolemy faked his data.
D) it had no explanation for retrograde motion.
E) the work of Tycho and Kepler showed the heliocentric model was more accurate.