SUMMARY OF KEY IDEAS

Focus Question 15-6

What negative consequence could arise from an alien civilization discovering a Pioneer spacecraft?

WHAT DID YOU THINK?

  • Why is water so important to the formation of life? Water allows many interactions between atoms and molecules dissolved in it.

  • What element is uniquely suited to be the foundation of life as we know it, and why? Carbon is the only atom that can bond flexibly (but not too flexibly) with three or more other atoms.

  • How do astronomers search for extraterrestrial intelligence? They search for radio signals from other advanced civilizations.

  • Have astronomers located any extraterrestrial civilizations? No. Extraterrestrial civilizations have not yet been discovered.

  • If advanced alien civilizations exist, is there any way they might know of our existence? Yes. They might detect our intentional radio broadcasts into space, our everyday radio and television broadcasts, or, possibly, one of our spacecraft traveling in interstellar space.