Read chapter 7 Long-distance calls:
http://books.google.com/books?id=PIjJ7_zttAkC&pg=PA47&lpg=PA47&dq=long-distance+calls+douglas+adams&source=bl&ots=QPG9vSPeYU&sig=j4hpzho7PMECSglGZPDy9pfYMuc&hl=en&sa=X&oi=book_result&resnum=3&ct=result#PPA47,M1
Quite likely, the universe is teaming with life, otherwise, as was said in the movie "Contact" it would be a waste of space.
