As I mentioned from the previous post on the Oort Cloud there are some scientists who are proposing that the components of life traveled on a comet from somewhere deep in the universe, possibly from the Oort Cloud, and then the comet collided with the earth generating a ton of power, and Bang! life was born. As cool as this sounds, it seems pretty science fictiony to me.
First, science has almost proven that the right kind of oxygen was not readily available in the universe to form life. Second, even if it was, I have a hard time seeing a bunch of precious molecules and atoms riding on the front of the comet surviving. Comets are super cold. Plus they go very near the sun and are exposed to extreme heat (granted if it hit the earth before it started swinging around the sun…). Then if the comet runs into small rocks and such, the life particles may have a hard time avoiding them.
Third, even if they did survive the odds of a comet hitting the earth are super low. One of the most probable rocks in space that could hit the earth is a rock that has a 99.99% chance of missing the earth. And that is one of the few things that will come close to the earth.* It would take billions of years just for a comet to hit the earth let alone for life to evolve…
Finally, if the comet did hit earth how would the life survive the impact? Not only that, but how would the earth respond. Scientists today say that if a large mile wide rock were to hit the earth the results would be devastating. Even if it were smaller (which reduces the odds of it hitting the earth) the result would be a lot greater than the effects of an atom bomb. How would simple life survive these results?
As you can see, I think it a very outlandish idea much similar to Michael Ruse’s explanation that life rode on the back’s of crystals** This is just one of the many ideas that Atheists are having to postulate in order to maintain their belief that there cannot be a God and that life must have originated by spontaneous generation and then evolved.
**- See explanation for the origin of life from Michael Ruse in the movie Expelled.