Moreover, the Sun's circular orbit about the galactic center is just right; through a combination of factors it manages to keep out of the way of the Galaxy's dangerous spiral arms. Our Solar System is also far enough away from the galactic center to not have to worry about disruptive gravitational forces or too much radiation.
When all of these factors occur together, they create a region of space that Gonzalez calls a "Galactic Habitable Zone." Gonzalez believes every form of life on our planet - from the simplest bacteria to the most complex animal - owes its existence to the balance of these unique conditions.
Because of this, states Gonzalez, "I believe both simple life and complex life are very rare, but complex life, like us, is probably unique in the observable Universe."
I disagree. I believe that life could exist in many different types of planetary environments. Life forms that we can't even relate to yet. Of course, like Gonzalez, it's just my belief.