Planets

Planets Our solar system consists of our sun, the nine planets with their moons, asteroids, meteoroids, comets, and lots of interplanetary dust and particles. Come and surf through the solar system and discover interesting facts about our little corner of the Milky Way!

The Nine Planets

What is the nearest solar system to ours?

This page has a listing of all the planets. Make a list of each planet and record the number of moons (also called satellites) that it has. Which planet has the most moons? Which planet has no moons?
Many of the moons have names. Who or what are most of the planets and moons named for?
Notice that OUR moon has no name! Think of a good name for OUR moon. Share your name with your class.

Saturn

The 6th planet from the sun.

In Roman mythology, what is Saturn the god of?
Who was the 1st person to observe Saturn with a telescope?
The satellite for the Cassini Mission was launched on Oct. 15, 1997. Its goal is to send back information about Saturn and its moon. When will it arrive at Saturn?
Saturn is one of the gas planets. What are the percentages of the gases of which it is composed?
How many of Saturn's rings can be seen from earth? The Voyager satellite sent back pictures of additional rings.
What are the rings of Saturn composed of?
If you are standing outside on a dark and starry night, can you see Saturn without a telescope?
When you are looking at objects in the night sky, how can you tell the difference between a star and a planet?
Saturn has more satellites (moons) than any other planet. How many? Is it possible that there are additional moons of Saturn that have not yet been discovered?

Pluto

The 9th planet from the sun. Pluto is the smallest planet. It is even smaller than some of the other planet's moons!

In Roman mythology, what is Pluto the god of?
List some of the other ideas that individuals had for the name of this planet. (From the main Pluto page, click on "other suggestions").
Who originally suggested the name "Pluto" and how old was this person?
Most of the other planets in our solar system have been known to man since ancient times. However, Pluto was only discovered in this century. What year was it discovered?
How was Pluto discovered?
Some scientists think that Pluto should be classified as a ______________ rather than a planet.
How is Pluto's orbit different than the other planets?
Pluto has one moon. When was it discovered and what is its name? Pluto's moon is the largest moon in the solar system in comparison to the planet to which it belongs. Earth's moon is the 2nd largest in comparison to its planet. Some scientists think of Pluto and its moon as a double planet rather than a separate moon and planet.

Venus

The 2nd planet from the sun.

This planet is named after the Roman goddess Venus. What is she the goddess of?
Venus is the brightest object in the sky except for the sun and moon. Historically, what two other names was Venus sometimes known as?
What was the first spacecraft t visit Venus in 1962?
Venus rotates very slowly. How many earth days does it take to make up one Venus day?
In its size and surface, Venus is most similar to what other planet?
Venus is farther from the sun than Mercury, but its surface is much hotter than that of Mercury. Explain why.
What do Venus and Hawaii have in common?
The moon is full of craters. Mars has craters. Even the earth has a few craters. Why doesn't Venus have any craters?

Neptune

The 8th planet from the sun. It's kind of like a huge, round popsicle.

This planet was named after the Roman god, Neptune. What was he the god of?
In what year was Neptune first observed?
Which spacecraft has visited Neptune?
Neptune is, technically, the 8th planet from the sun. However, sometimes it is the 9th planet from the sun. Why?
What is the surface of Neptune mostly composed of?
What 3 gasses make up most of the atmosphere of Neptune?
Why is Neptune blue?
What was Neptune's most prominent feature called? Scientists weren't even exactly sure what it really was. What happened to it?
Did you know that Neptune has rings just like Saturn? Observations from the earth have never shown them clearly, but when Voyager 2 passed that way, the rings were clearly visible. How many rings does Neptune have? The rings even have names! What are the names? Do they sound like names from mythology?
If you're star/planet-gazing in your backyard on a dark and clear night, can you see Neptune?

Mercury

The closest planet to the sun.

Mercury is named after a Roman god. What was he the god of? Who is his Greek counterpart?
Pluto was just discovered in 1930, but most other (closer) planets were known and observed by ancient peoples. According to this site, approximately how long ago did people start watching Mercury?
Mercury has only been visited by one spacecraft. ("Visited" implies that spacecraft with imaging satellites fly near the planet and transmit back photographs of the planet. They do not actually land on the planet--except for Mars). What was that spacecraft?
Why hasn't the Hubble Space Telescope (HST) been able to safely map Mercury?
What is the temperature range on Mercury?
What is the densest body in our solar system?
Like our moon, Mercury has many craters. What condition is similar on both bodies that make it have many craters?
How many moons does Mercury have?
If you're star/planet-gazing in your backyard on a dark and clear night, can you see Mercury?

Jupiter

The 5th planet from the sun.

Jupiter is huge! How big is it compared to all the other planets?
What was Jupiter's role among the rest of the Roman gods? Who was his Greek counterpart?
Jupiter is the 4th brightest object in the night sky. What are the 1st, 2nd, and 3rd brightest objects?
Who first discovered Jupiter's 4 large moons? In what year did this person discover them?
What spacecraft first visited Jupiter?
What spacecraft is currently in orbit around Jupiter?
What kind of surface does Jupiter have?
What two main gasses make up Jupiter and in what percentages are they found?
What is the core of Jupiter probably made up of?
Jupiter is famous for having something that scientists call the GRS. What do those initials stand for? How big is the GRS in comparison to the earth?
Jupiter actually has rings like Saturn! What are they made of?
In July 1994, what collided with Jupiter?
Jupiter has 16 moons--4 big ones and 12 smaller ones. What are the names of the 4 large moons? Who were they named after?

Mars

The 4th planet.

Mars is named after the Roman god of war. Before he was the god of war, what was Mars associated with. How might this fit in with the future of Mars?
After the earth, Mars is the most studied of the 9 planets. List the spacecraft that have visited Mars and when they visited.
In Fahrenheit, what is the average temperature on Mars? What is the range of temperatures on Mars?
Explain why Mars has about the same amount of land surface area as earth even though Mars is much smaller.
Mars has the highest mountain in the entire solar system. What is it and how tall is it? What is the tallest mountain on earth? How high is it? (Use this resource: http://www.scaruffi.com/travel/tallest.html). Look at this mountain chart again. The top 25 highest mountains on earth are all in Asia! On what continent is Tallest Mountain #26? On what continent is Tallest Mountain #27?
Hellas Planitia is one of the biggest craters on Mars. It was caused by the impact of a meteor. How wide and deep is it? What are the names of 2 of the biggest craters on earth and where are they? (Use this resource: http://www.3datlas.com/list_gl.html#Crater).
What are the Valles Marineris? How were they formed?
What gases in what percentages make up Mars's atmosphere?
What are the ice caps on both poles of Mars made of?
What was concluded about the evidence of life on Mars from the data gathered from the Viking exploration?
Can you Mars at night without a telescope?

Earth

3rd rock from the sun.

How is earth's name different than the other planets? If the naming of earth had followed the pattern for the other planets, what might earth's name have been?
In what century did we finally figure out that the earth is actually just a planet? In what century did we finally have maps of our entire planet? What aided in the mapping of earth?
List the layers of the earth.
Compare the thickness of the earth's crust under the continents to the crust under the oceans.
Which layers of the earth are solid and which are semi-fluid?
Most of the mass of the earth is in what layer? In which layer is most of the rest of the mass?
What element makes up the composition of most of the core of the earth?
What is the approximate temperature of the inner core of the earth? How does it compare to the temperature of the sun?
What is the lower mantle of the earth composed of? What is the upper mantle composed of? What is the crust composed of?
Describe plate tectonics. How many major plates are there? About how many small plates are there? What phenomenon is common at the boundaries of plates?
What percentage of the earth's surface is covered with water? In our solar system, where else does water exist in liquid form? What role does the heat capacity of the oceans play in our climate? What other process is liquid water responsible for on earth that is unique in the solar system?
What is the atmosphere of the earth made up of?
What causes the aurora borealis?
What are the Van Allen radiation belts? What produces them?

Uranus

The 7th planet.

Who discovered Uranus? When was it discovered? It had been seen previously, but what did early observers think it was?
What names did this planet have before it was officially named "Uranus"?
Uranus has only been visited by one spacecraft. Which one?
What is Uranus primarily composed of?
What is the atmosphere of Uranus composed of?
Did you know that Uranus has rings? How many?
How many moons does Uranus have? Unlike the names of other planets and moons that come from mythology, where do the names of the Uranus's moons come from?

Author: LINDA MOSBACKER - Email linda.mosbacker@slc.k12.ut.us