The truth about so-called habitable planets. They will be extremely rare
Channel: Artifactsofmars
Date: 13/06/2017

What scientists don't explain is that there is only one mono atomic gas that can mix with oxygen to make an atmosphere breathable, and that is nitrogen. Helium is too light, and other gasses too rare. Just the atmosphere alone will make so-called class M (Star Trek term) rare. Then you have temperature, presence of water, vegetation and more to consider. Any planet that is inherently habitable by humans will be extremely rare therefore. Yet we are bombarded by stories of planets in the so-called Goldilocks zone. 
    I got started on this by a somewhat related topic, bacterial life. The plants on Mars are ignored by the media and NASA.