When Is a Planet Not a Planet?

What is the main idea of the article "How Pluto Stopped Being a Planet"?

• A group of astronomers decided that Pluto is a dwarf planet.

• Pluto is large enough to be a moon but too small be a planet.

• Many astronomers are pleased that Pluto is not a planet anymore.

• Some astronomers still believe Pluto should be called a planet.

Which statement from the text BEST supports the main idea of the article?

• "For decades, people believed our solar system had nine planets..."

• "And it's true that Pluto is small compared with the planets."

• "In August 2006, astronomers came up with a new definition of planet."

• "It has to be massive enough for its own gravity to pull it into the shape of a ball."

Which of these is MOST CLEARLY a key detail of the passage?

• "And it's true that Pluto is small compared with the planets."

• "If Earth were the size of a basketball, Pluto would be the size of a golf ball."

• "It hasn't cleared its neighborhood the way the planets have."

• "Not all astronomers accept the change to Pluto's status.'

What is the BEST meaning for the word "dwarf"?

• angry

• huge

• small

• enough

Why did the author MOST LIKELY write this article?

• To entertain you with a story about Pluto.

• To persuade you to find another planet to add to our Solar System.

• To provide information about why Pluto is no longer considered a planet.

• To write a story for you to enjoy.

Which sentence BEST summarizes the article "How Pluto Stopped Being a Planet"?

• Pluto is now a "dwarf planet" because it does not meet the three conditions to be a planet.

• Not all astrononers believe Pluto is now a "dwarf planet".

• Our Solar Sytem no longer exists.

• A lot of "dwarf planets" exist inour Solar System.