Drake
Equation
Understanding the Terms:
percent of habitable planets with life
  back to full equation
This term, percent of habitable planets with life, acknowledges that having a planet that is appropriate for life doesn't necessarily mean that life arises on that planet.

No real data are available to help us estimate a value for this term-Earth is the only planet on which we know there is life. Some scientists believe that life is inevitable-that if conditions are appropriate, life will arise (100%); indeed, bacterial life existed on Earth very shortly (in terms of geological time) after the planets' formation, possibly indicating that the development of life is easy. Others believe that life is a rare accident-something happened here on Earth but is not likely to happen elsewhere (.000001%). And of course, many fall somewhere in between, believing that whether or not life arises depends on many factors.

Percent of habitable planets with life:
This percentage will be shown using the diagrams below.

dead planet  = not habitable     habitable planet  = habitable     habitable planet with life  = habitable w/ life
Note: this diagram is not meant to accurately display the
scale, position, or color of planets in any solar system.

 
Your current choice for this term:

To update this value, return to the full equation page and change the value in the form.
  previous term in equation  |  full equation  |  next term in equation