___ 1. Solar system
___ 2. Orbit
___ 3. Mantle
___ 4. Astronomer
___ 5. Gas giant
___ 6. Atmosphere
___ 7. Asteroids
___ 8. Water ice
___ 9. Probe
___ 10. Kuiper belt
A. A term scientists use to describe frozen water, to distinguish it from ice that forms from other chemical substances.
B. The path that a smaller body takes around a larger body.
C. A ring of icy objects orbiting in the outer solar system beyond Neptune.
D. A group of bodies in space made up of a star and the planets and other objects orbiting around that star.
E. The mass of gases that surrounds a planet.
F. A scientist who studies stars and planets
G. The area of a planet between the crust and the core.
H. An unpiloted device sent to explore space. Most probes send data (information) from space.
I. A small body made of rock, carbon, or metal that orbits the sun.
J. Any of four planets – Jupiter, Saturn, Uranus, and Neptune – made up mostly of gas and liquid.
Part II: Multiple Choice
1. Neptune is the ______ planet from the sun.
2. Neptune appears bright blue because:
A. It is entirely covered in water.
B. Its surface is mostly made up of copper.
C. It reflects the color of one of its moons.
D. There is methane gas at the top of its atmosphere.
3. Although astronomers are unsure what the center or _______ of Neptune is made of, it is most likely composed of ice and rock.
4. So far, how many moons have astronomers detected orbiting Neptune?
5. The streams of nitrogen and other materials that sometimes spurt from beneath Triton’s surface are called:
A. hydrothermal vents
B. black smokers
6. Why was the planet named after Neptune, Roman god of the sea?
A. Because it is covered in water.
B. Because of its connection to the moon Triton.
C. Because of its blue, watery color.
D. Because Neptune’s discoverers hoped to find sea life on the planet.
7. A small body made of dirt and ice that orbits the sun is called a:
B. dwarf planet
8. Long-period comets come from a part of the solar system called the:
A. Kuiper belt
B. Oort cloud
C. Van Allen belt
D. Kennelly-Heaviside layer
9. Pluto is a _________, or an icy object that is larger than a comet or an asteroid, but too small to be considered a planet.
A. gas giant
D. dwarf planet
10. In 2006, a spacecraft called “New Horizons” was launched with a mission to:
A. Land on Neptune and gather data.
B. Fly past Pluto to gather data on the dwarf planet
C. Fly as far out into the universe as possible and gather data.
D. Land on Charon and gather data.
Part III: Short Answer
1. Why is it unlikely that there would be life on Neptune?
2. What is the name of the largest dwarf planet astronomers have identified so far?
3. Why are Eris, Makemake, and Haumea all called “plutoids”?
4. What is the name of the space mission that visited Neptune?
5. What are the names of two of Pluto’s four moons? [Note from sd: A fourth moon, P4, was discovered in July 2011.]
Part IV: Critical Thinking Essay
Based on what you know about Neptune, comets, and dwarf planets, what do you think are the benefits and drawbacks of space study and exploration?
To discover more about the solar system, visit World Book's reference website list.