The likely hood, even for skeptic's, that Life exists elsewhere in the universe is huge.  Infinity is a guaranteed absolute (an infinite number of all things existing in all directions for infinite time) yet even denying this and believing that there are a limited number of possibilities Dr Frank Drake Chairman of the Board of the SETI institute, developed an equation in 1961 to illustrate the probability of there being life elsewhere in the infinite Universe.

 The Drake Equation, as it has become known, identifies specific factors thought to play a role in the development of such civilizations. Although there is no unique solution to this equation, it is a generally accepted tool used by the scientific community to examine these factors.
--Frank Drake, 1961 (for more information please visit the SETI web-site)

 
The equation is usually written:
N = R_* • f_p • n_e • f_l • f_i • f_c • L
 

N	= The number of civilizations in The Milky Way Galaxy whose electromagnetic emissions are detectable.
R*	=  The rate of formation of stars suitable for the development of intelligent life.
fp	=   The fraction of those stars with planetary systems.  ..... Number of probable planetary systems.
ne	=  The number of planets, per solar system, with an environment suitable for life.   This Number is likely to be ......
fl	=  The fraction of suitable planets on which life actually appears.  We are not yet technologically advanced enough to answer this question or those beyond.... yet.. But as Gandhi said..    ''Just because no one sees the truth does not make it an error''.
fi	=  The fraction of life bearing planets on which intelligent life emerges. For more information, please visit               Dr. William Calvin's .  Click for "The Drake Equation's fi"
fc	= The fraction of civilizations that develop a technology that releases detectable signs of their existence into space.
L	= The length of time such civilizations release detectable signals into space.

As a highly respected scientist created such an equation in order to illustrate this very simple probability (setting aside the absolute of infinity - meaning if we exist therefore so will an infinite number of other civilizations also exist, who are both,  as advanced as us and more advanced than us. There will also be an infinite number yet to advance.)  Do you feel that this probability is 'just that' a probability?