[JurijD]

Hmmm I don´t agree with you at all. What you are describing (the distance to the Sun, the influence of the Moon, H20 etc. etc.) are all conditions that had to be met for a planet to turn out the same as Earth... but life can exist in countless different contidions. If Earth had a SO2/CO2 atmosphere mix (with 0% oxygen) and a temperature of say 150°C, forms of sulfur bacteria (that we know of today) would be plentiful all over the globe... and with those kind of gasses in the atmosphere it would get so dense that even water could exist in liquid form at temperatures higher than 200°C...Life is very very tough...the usual range of 0 to 100°C + water + oxygen is only limiting to very complex organisms (that we know of!) what I am trying to say here is that you must not limit yourself to planets that are similar to Earth. One of the best "conditions" for life is the presence of water and a rich "soup" of anorganic/organic compounds in the planets atmosphere and crust. I think life will be very plentiful in the universe, we will prolly find it in many solar systems... another question all together is how much of that will be intelligent and not only a green blob of goo on a rock somewhere... that noone can answer because we just don´t know how frequent intelligence comes around (we only know of one example on earth) we´ll just have to wait and see.