LIFE IN THE UNIVERSE — ^HITANG 249 



(p, 140). So far, Project Ozma observations have given negative 

 results. 



It is generally agreed among radio scientists that the best frequency 

 to employ is that of the 21-cm. neutral hydrogen line. It has been 

 suggested that the value of pi, or the fine structure constant, or any 

 other dimensionless constant, be transmitted in order to distinguish 

 our signal from natural sources of radio noise. I personally think 

 a great effort of this kind inadvisable, however fundamental the con- 

 stant might be. 



Instead, I suggest using simple numbers : 1, 2, 3, each represented 

 by the corresponding number of dots. They are as good a sign of 

 intelligence as any physical or biological constant. Then we could 

 proceed to introduce the concept of equality and other algebraic sym- 

 bols (as P. Morrison has also proposed). This can be done by coding 

 such symbols and repeating a large number of examples, just as 

 arithmetic is taught to children. At this stage the binary, decimal, 

 or some other number system may be introduced, and finally the a?, y 

 concept of locating a point on a plane. Once this is established, a 

 means for interchanging information follows easily. 



While the chances of success in receiving intelligible signals from 

 outer space are extremely small, even during a long search with larger 

 and larger radio telescopes, it is worth trying because of its funda- 

 mental importance in miderstanding the nature of living beings and 

 its impact on our pliilosophical beliefs. 



