Fermi's Paradox

Fermi's paradox simplified:

• Earth is 4 billion years old
• Life started 3.5 billion years ago
• We (homo sapiens) arrived about 200,000 years ago
• During the last 50,000 years we became intelligent because of technological innovation (future post)
• We've been traveling to outer space for 50+ years.
• Let's optimistically assume we survive another 10 million years (many species have done this) if we don't ruin our planet (big if).
• We should be able to travel across the galaxy by that point in our timeline
• So, roughly, if the law of averages applies, once life takes root on a planet (or moon), 3.51 billion years later, that life has explored the outer reaches of the galaxy.
• Our galaxy, the Milky Way is 13.2 billion years old
• There are approximately 200 billion stars (solar systems) in our galaxy.
• Our galaxy has had a 9.2 billion year head start on our solar system.
• If life is a natural common occurrence throughout the galaxy, where is everybody?

This is Fermi's paradox.  Because of our late arrival to the galaxy, we should have already been visited by thousands, if not millions of advanced civilizations.  Why haven't we?  Or if we have, why is there practically no evidence to prove it.  Yes, we are inundated daily with reports of UFO's across the world but I disregard this for lack of solid proof.  As the great Carl Sagan stated, "extraordinary claims require extraordinary evidence".