How Scientists Look: teacher key

Aliens and UFOs, grade 7 edition, written for 7th grade. Scientists look for life beyond Earth with rovers on Mars, telescopes in space and radio dishes. Strange lights in the sky get checked too, and many turn out to have ordinary causes.

Read the book. Print this page for the key.

Questions and answers

1. What does a transit mean when scientists look for planets?
   • A planet passes in front of its star (answer)
   • A rover drives across a crater
   • A star turns red
2. What is the habitable zone?
   • A crater on Mars
   • The area around a star where a planet could have liquid water (answer)
   • A place where radio signals are made
3. What do the letters UFO stand for?
   • Unusual flying orbit
   • Unidentified flying object (answer)
   • Universal flight observer
4. Curiosity found evidence of past habitable environments. What does that tell us?
   • Life was found on Mars
   • Mars was never wet
   • Microbial life could have lived in those places (answer)
5. What does unidentified mean for the 701 Blue Book cases?
   • They were proved to come from space
   • The cause was not named (answer)
   • They were all hoaxes
6. What does the word rogue describe in rogue planets?
   • Planets with rivers
   • Planets that orbit no star (answer)
   • Planets made of rust

Words

• exoplanet: far-off planet
• transit: passing in front
• habitable: livable
• rover: wheeled robot
• unidentified: not yet named