I forgot to add that, Robert. of course you have to have some criteria, for no classification could be done without that.
Hamza, the problem with the religious people is that they want to fit everything into their beliefs, so that they could call themselves enlightened. right now you are saying that the "seven" layers of atmosphere are the seven heavens while each one makes the "earth" for the next one. that is only because there is no scientific evidence to support there are seven earths. and the Layers of Earth are divided into Three only (crust, mantle and core). even if today that classification is replaced with another one that contained seven layers, you will then change your statement. and say " aha. see God had told us 1400 years ago. now it is being proven by science"..
the thing is that anything that is disproved by Science is never taken as an evidence that there couls something be wrong with the faith.
so the matter is like this. when something that is in the religion is supported by scientific evidence, you take is as evidence of the religion's truth. if something comes up against the beliefs, then you dont want to to own that evidence until something favorable comes up.