Listen&Learn: The Fermi paradox

Learn about the problem with the idea of alien life.

Pre-listening vocabulary

• paradox: a problem that appears to make no sense
• develop: to grow and progress
• civilization: a society of intelligent beings
• interstellar: between different star systems
• propose: to offer an idea
• hypothetical: possible, but not proven

Listening activity

Podcast: Play in new window | Download (Duration: 1:19 — 1.2MB)

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Gapfill exercise

The Fermi paradox is based on a question asked by a scientist named Enrico Fermi: if the is so large, why haven’t we found intelligent life yet? Although it is a very simple question, it has confused scientists for . The universe has existed for over 13 billion years, but our planet is only about 4.5 billion years old. Fermi believed that if human life could develop so quickly, there surely had to be older, more civilizations out there. These civilizations likely would be capable of interstellar travel. If this is true, then should have contacted us already. Many people have proposed since Fermi first asked the question in 1950. One possibility is something called a Great Filter, which is a hypothetical barrier that stops most types of life from developing past a certain point.

Comprehension questions

See answers below

1. The universe is about
   a. 4.5 billion years old
   b. 13 billion years old
   c. 50 billion years old
   
2. Fermi thought that if older civilizations existed,
   a. they should have contacted us already
   b. they wouldn’t be friendly to us
   c. they would have destroyed each other
   
3. The Great Filter is
   a. a hypothetical barrier that stops life from developing
   b. a hypothetical type of technology for interstellar travel
   c. a hypothetical civilization that has the power to contact other civilizations

Discussion/essay questions

1. Do you believe in life on other planets? If so, why do you think they haven’t contacted us? If not, what makes you think we’re alone?
2. Scientists who believe in the Great Filter are not sure if we are past it. What could stop life on Earth from developing further?

Transcript

The Fermi paradox is based on a question asked by a scientist named Enrico Fermi: if the universe is so large, why haven’t we found intelligent life yet? Although it is a very simple question, it has confused scientists for decades. The universe has existed for over 13 billion years, but our planet is only about 4.5 billion years old. Fermi believed that if human life could develop so quickly, there surely had to be older, more advanced civilizations out there. These civilizations likely would be capable of interstellar travel. If this is true, then aliens should have contacted us already. Many people have proposed explanations since Fermi first asked the question in 1950. One possibility is something called a Great Filter, which is a hypothetical barrier that stops most types of life from developing past a certain point.

Answers to comprehension questions

1b 2a 3a