# Quiz 1. An Alien Clue?

 Name: ________________________ Given 8/24 ID Number: ________________________

Suppose we receive a signal from aliens living on an earth-like planet in another star system, and make some progress in decoding their message. But the aliens seem to have left out one vital piece of information -- nowhere do they explain what they use for a unit of length. They give their own size and all sorts of other useful information, but we can't convert these sizes into our units because we don't know how many meters there are in an `alien length unit' (abbreviated alu).

Among the things we have been able to partly decode is the diagram above. We can read the numbers and we know that the diagram shows sizes of objects measured in alu, but we don't know what the arrows indicate because the aliens use their own names for things.

Does this diagram give us any clues about the size of the alien length unit? If so, explain how it does, and try to estimate how many meters there are in an alu. If not, give a reason why not.

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 Joshua E. Barnes (barnes@ifa.hawaii.edu) Last modified: August 23, 2006 http://www.ifa.hawaii.edu/~barnes/ast110_06/quizzes/quiz01.html