Distance

Distance is important to us. Planet is has a certain distance  from our sun. This is the habitat zone... It is the proper measure. OK so any further and the oceans would freeze solid into a block of ice. Also, if it was closer to our sun... the very seas would in fact boil away. Certainly, this window is very narrow. Perchance a bit too narrow for us. It is true that our sun gains energy every year. Eventually our oceans will and can boil away.