Here is a link to another blogger’s commentary on the very recent discovery of Kepler 452b, an “extrasolar” planet orbiting a nearby star, illustrating very intelligibly why so much fine-tuning is necessary in order for any planet to be habitable for life, especially complex life:

http://rtbsydneychapter.blogspot.com.au/2015/07/is-kepler-452b-really-earth-20-bigger.html

Anthony and I are members of what Reasons to Believe calls its “apologetics community.”  I took a training course and was granted admission to their bulletin board in which approx. 250 scientists and lay people from many backgrounds from all over the world participate.  (It looks like Anthony is in Australia!)  Generally I can get several knowledgeable answers to most technical questions in a day or two.

The original article appears above the line; Anthony’s comments are below.  Enjoy!