Google "Near Death Experiences".
or
NEAR DEATH EXPERIENCE RESEARCH FOUNDATION (NDERF) (thousands of people explaining their NDE in bold detail)

God probably exists because so many people say the exact same thing for years. The real research is to examine the people who have passed on and came back to life. Once you die your physical conscience of the brain stops, leaving behind 'whatever' is left.

Most say, "I all-of-a-sudden felt my Spirit leave my body, entering a tunneled vortex, at the end was a Brilliant white light. They are without a body traveling at super sonic speed towards the white light." At the end of the Tunnel they meet a 'being' of some kind be it God, or a passed on relative to greet them.