The oxygen planets are meant to be N2 O2 atmospheres. That is exactly what they were called in SE3.
I am not even sure if it is possible to have an atmosphere of entirely O2. The only reason why there is any O2 in Earth's atmosphere is because there are tons of plants and photosynthetic algae in the oceans that release it. Before life evolved on the earth, there was very little free floating oxygen in the atmosphere.
Slick:
What Kwok said.
My point about the Drake equation was that you should not just accept things that people tell you; you should always be doubtful and question them, exploring the possibilities to figure out for yourself if they are right or not. Many things that have been taught in universities over the centuries have turned out to be wrong.
[ February 21, 2003, 20:13: Message edited by: Imperator Fyron ]