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For many years humans have looked for evidence that life may exist elsewhere in the universe. In this activity you are to locate and evaluate evidence for the existence of life in the Universe beyond Earth.

Most scientists consider the requirements for life as the most important factor for finding other life forms. For the likelihood that life exists beyond Earth, there must be:

  • Water
  • An atmosphere
  • Enough energy

A scientist at the National Radio Astronomy Observatory in Green Bank, West Virginia, Dr. Frank Drake, determined how to estimate how many technologically advanced civilizations might be in our galaxy. The equation does not have a definite solution, but it makes an interesting way to consider the topic. Here is the equation and how it works:

Don't let this scare you! You don't have to actually DO the math unless you want to. Click on the equation to see what each part represents.

N = R* x fp x ne x fl x fi x fc x L

Just for fun, let's do an example. Assume there are currently 100,000,000,000 stars in the Milky Way.  Plug that number into the equation for R*. For our example we are going to have each of the fractions in the equation equal to 1/100 and assume that each solar system would have only one planet supporting life. Ignoring the length of time signals are released and the fact that stars are constantly dying and being born, and the equation would be:

N = 100,000,000,000 x 1/100 x 1 x 1/100 x 1/100 x 1/100

N = 1000

This means, according to our equation, that there could be 1000 planets with technologically advanced civilizations!

Some scientists are searching for evidence that other planets exist in the universe. In recent years, astronomers have successfully shown that planets exist around many distant stars. The NASA Space Interferometer Mission (SIM) and Terrestrial Planet Finder Mission (TPFM) are designed to locate more Earth-sized planets around other stars in our galaxy.


Answer the following questions:

  1. What tools what you need to find life on other planets?
  2. How do you define "life"?
  3. Why would someone want to seek life on other planets?

Take the tour “Life in the Solar System

  • Choose one tour from the same site on Mars to explore.
  • From the tours you took, what can you add to your answers above? Think of at least two questions you can now ask.

The following sites are from Nasa and SETI. Explore each one. Look for information about what is currently being done to find life on other planets. Write notes about each site as you go.


Demonstrate what you know:

Do you agree or disagree with spending money and using resources to find life on other planets?

What evidence do you have to support your opinion?

Task – The company you work for has asked you to design a poster for distribution across the country supporting their opinion about life on other planets. The only problem is your company’s opinion is the opposite of yours. Design your poster to represent your company’s opinion. Be sure to include at least 4 pictures, correct and current information. Don’t forget to check spelling and grammar. Your boss mentioned that their will be a bonus if he likes your work. Check out the rubric to make sure you do the best work possible on this task!



  1. WHO-WHAT-WHEN-WHERE-WHY POEMS Write a five-line poem to represent your opinion. Each line may be a word, a phrase, or a sentence. You may change the order of the questions.
    • Practice
    • Run around the track every morning
    • In the hour before school
    • Back behind the gym
    • I want to win the big race
  2. Create a BUMPER STICKER
    Bumper stickers are a great way to express your opinion in an artistic manner. Choose an appropriate symbol or slogan and have fun.
    • Heavy, white art paper
    • Markers, colored pencils, paints
    • Scissors
Review science lab safety rules here.

Get the plug-ins: Get Adobe Acrobat Reader and Get Quicktime Player. (The QuickTime plug-in is needed to play sounds and movies correctly.)

Want to share photos of you or your friends doing this activity? Send it in an e-mail with the following information:

  1. The title of the activity
  2. The URL (Internet address)
  3. Your name.

Remember that no pictures can be used that show student faces or student names on it. 

Teachers should view the Teacher Site Map to relate Sci-ber text and the USOE Earth Systems Science core.


Updated October 24, 2008 by: Glen Westbroek

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