We live on a planet uniquely and delicately balanced to sustain life. In The Privileged Planet, a documentary put out by Illustra Media, scientists describe over 20 factors which have to be in place all at the same time for carbon-based life to exist on any planet.
Liquid water is one of them.
The planet must have a certain mass and move in a nearly circular orbit at a moderate rate of rotation around a G2 dwarf star just the right distance away.
The planet must be orbited by a large moon to stabilize its tilt.
It must be a terrestrial planet with an oxygen-rich atmosphere and just the right ratio of liquid water and continents.
The continents must move flexibly, in accordance with plate techtonics.
There must be a protective magnetic field.
The chances of all these 20 or so factors being in place at the same time for a single planet are 1 in one-thousandth of one in one-trillionth, if I copied down the information correctly. The distance of our planet from the sun alone cannot deviate 5% closer to the sun or our temperatures would be 900 degrees F; 20% further from the sun would turn our atmosphere to ice.
Scientists call this narrow habitable zone the “Goldilocks zone.” It has to be just right.
Aimless blundering–no matter how much time you allow–can’t account for such precision.