Answers are at the end.


1) Which statement about planetary orbits is incorrect?

A) All planets orbit the Sun counterclockwise.

B) Most stay close to the earth's equator in the sky.

C) Most orbits are almost circular, with low eccentricities.

D) All have the Sun at one focus of their elliptical orbits.

E) Most also rotate counterclockwise on their axes as well.


2) Iron meteorites are believed to come from:

A) the core of a differentiated asteroid, now broken up.

B) the crust of a differentiated asteroid, now broken up.

C) a broken up cometary nucleus.

D) debris from the Kuiper Belt.

E) interstellar space.


3) Long-period comets are believed to originally come from:

A) the asteroid belt.

B) the Kuiper belt.

C) the Oort cloud.

D) the satellite system of Jupiter.

E) the interstellar medium.


4) The orbits of most comets:

A) lie almost entirely beyond the orbit of Neptune.

B) have perihelions inside the orbit of Mercury.

C) have aphelions in the Kuiper belt.

D) are smaller than the orbit of Comet Halley, with a 76-year period.

E) are open, going out into interstellar space, and thus never return.


5) The impact of a fragile body in June 1908 produced a huge explosion over:

A) northern Canada.

B) Alaska.

C) Siberia.

D) Mars.

E) the Moon.


6) Which planet by itself contains the majority of mass of all the planets?


B) Saturn

C) the earth

D) Venus

E) Uranus


7) In what part of the atmosphere does life occur?

A) exosphere

B) stratosphere

C) mesosphere

D) ionosphere

E) troposphere


8) Which planet shows the widest range of surface temperatures between day and night?

A) Mercury

B) Venus

C) Earth

D) Mars

E) Uranus


9) Which body has the densest atmosphere?

A) Mercury

B) Venus

C) Earth

D) Mars

E) our Moon


10) Which of these gets brightest; so bright as to be seen during daylight at times?

A) Mercury

B) Venus

C) Mars

D) Jupiter

E) Saturn


11) Two planets have orbits with the same sized semi-major axis. Which is true?

A) The planet with the most eccentric orbit moves faster all the time.

B) The planet with the most eccentric orbit moves faster some of the time.

C) The planet with the most eccentric orbit never moves faster.

D) Not enough information to answer.


12) A planet orbit could be circular.

A) True

B) False


13) Assume a planet orbits exactly three times as far from the Sun as the Earth.

A) It’s period is 3 years exactly.

B) It’s period is between 3 and 5 years

C) It’s period is between 5 and 7 years

D) It’s period is 7 years or more.


14) Which feels hotter?

A) 300° F

B) 300° C

C) 300° K


15) Which will have the greatest effect on a planet’s temperature?

A) doubling a planet’s distance to the sun

B) doubling a planet’s albedo

C) doubling a planet’s mass

D) doubling a planet’s rotation rate


16) The direction in which a comet's tail points is determined by

A) The Sun's gravity

B) The Earth's gravity

C) The solar wind

D) The comet's direction of motion


17) A histogram of comet periods would show

A) Many comets with periods shorter than 200 years, but few with longer orbits

B) Many comets with periods shorter than 200 years, and many with much longer periods (thousands of years), but few in between

C) Many comets with periods longer than 200 years, but few with shorter orbits

D) Approximately equal numbers of comets at periods ranging between 0 and 10,000 years


18) What is a distinguishing characteristic of planetesimals that enabled planets to form?

A) They were sticky enough to hold clumps of matter they encountered.

B) They were the final stage of planet formation, just before forming an atmosphere.

C) They had sufficient mass to gravitationally attract more material and thus grow larger.

D) They were formed by the fragmentation process.


19) What happens when the solar nebula contracts?

A) It flattens out

B) It spins faster

C) It heats up

D) All of the above


20) Why do other terrestrial planets appear more heavily cratered than Earth?

A) More impacts have occurred on other planets

B) Earth's missing craters are hidden under the oceans

C) We haven't searched the Earth thoroughly yet

D) Erosion (e.g., wind and rain) has erased craters from the Earth


21) Has a spacecraft ever landed on the surface of Venus?

A) Yes

B) No, the atmosphere is too thick

C) No, the surface temperature is too high

D) No, the atmosphere is too corrosive


22) The fact that most of the impact craters discovered on Earth are located in Europe and North America demonstrates that

A) We have searched those locations the most thoroughly.

B) Magnetic interactions with iron-based asteroids favor northern hemisphere impacts.

C) Earth’s gravitational pull is slightly stronger in the northern hemisphere.

D) Harder soil in the southern hemisphere makes its craters smaller and harder to find.


23) The coma of a comet is made of

A) Solid rock

B) Solid ice

C) Liquid water and ammonia

D) Loose material, gas and dust


24) Where is a comet's tail the shortest?

A) Perihelion

B) Aphelion

C) Perigee

D) The length of a comet's tail does not change


Key:     B A C A C     A E A B B     B A C B A     C B C D D     A A D B