Lesson 14 Alien worlds

Scientists believe that in the past, Mars may have been _______ for ______.

• discover/ dark

• suitable/ life

• near/ distance

• single/ excited

The ________ from Earth to the sun is about 150 million kilometers.

• distance

• life

• within

• dark

It takes around eight minutes for its light to _____ us.

• near

• excited

• discover

• reach

Astronomers _______ the planet Pluto in 1930.

• discovered

• discover

• discovering

• discovers

Scientists were ______ to find water on Saturn’s moon Enceladus.

• suitable

• dark

• excited

• near

Earth has only a _____ moon, while Jupiter has 67.

• within

• single

• near

• suitable

On a(n) _____ night, you can see more stars.

• dark

• excited

• single

• suitable

It’s possible that ______ 25 years, humans will travel to Mars.

• distance

• reach

• near

• within

New technology is helping astronomers _______ hundreds of new planets.

• reach

• suitable

• discover

• near

Our ______ star system, Alpha Centauri, is 4.3 light-years from Earth.

• life

• single

• within

• nearest