Is There a Shadow Biosphere?

There are lots of different definitions of life that are in competition with each other. You want to make sure you 're defining your terms properly, because if your definition of life is overly inclusive, it could lose all meaning. I was reading an article by an astrobiologist named samantha rolph, and she points out thate're probably more than a dred legit definitions of what constitutes a life form. Most of them encounter some potential objections here or there.