Using Binary to Send
Messages into Space

Objective:
To show how messages are sent into space using radio telescopes with the hope that the messages will be received and understood by intelligent life in other solar systems.

Activities:
The students will:
  1. Decode a message that is written in binary code.
  2. Study an actual message that was sent by the Arecibo radio telescope.
  3. Design a simple picture on graph paper and code it in binary.

Materials:
For each student:
graph paper, pencil
copy of 10 by 10 binary code chart
copy of message sent from Arecibo
For the lesson:
Arecibo message with the explanations of some of the symbols
drawing of key to show what binary chart looks like uncoded

Previous Knowledge Necessary:
Knowledge of binary code (ties in with a lesson about computers)

Some background about radio telescopes, which are used to send and receive radio signals. They can be used to communicate with our deep space exploratory probes and with possible extrater restrial life, although they are most commonly used to listen to the radio noise of outer space.

Procedure:
  1. Using a copy of the binary code chart, each student transfers the binary lines onto her graph paper, leaving the square blank if the number is "0" and filling in the square if the number is "1."

    (The finished product is a drawing of a key with the word KEY underneath.)

  2. Have the students look at the picture that was acturally sent by radio telescope. Explain tha the message is coded in binary, but if any intelligent extraterrestrials find the message, they may be able to figure out that they can decode the binary by doing exactly what the students did actuallythewith the "key" message. See if anyone can guess about the meaning of the symbols portrayed in the picture. (A copy of the symbols with simple explanations of the meaning is enclosed.)

  3. The students can then draw a simple picture on graph paper. Then they can code the picture in binary by assigning "0" to the blank squares and "1" to the colored squares.

  4. Binary code message can be traded with friends or by lot and decoded by transferring the binary message onto graph paper. (This activity is the same as the first procedure.)

This activity was taken from a book by Harold R. Jacobs titled Mathematics - A Human Endeavor. It was published by W. H. Freeman and Co., San Francisco in 1971.

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