# mathematics, as a universal language

It has often been pointed out that despite the great differences between
cultures and natural languages on Earth, mathematics is the same the world
over. In fact, scientists are inclined to believe that mathematics and the
mathematical rules which underpin nature are universal, so that all intelligent
races in space have at least this much in common. Since the fundamental
properties of numbers are the same everywhere, these can be used as the
basis of interstellar messages. Binary numbers
and prime numbers, in particular, being
so fundamental, are considered to be of great importance in SETI.
They underpinned the Arecibo Message and
provided the initial clues to the decipherment of the alien signals in Carl Sagan's *Contact* and Fred Hoyle and John Elliot's *A
for Andromeda*.