It takes more than just temperature and an iron core to make a planet hospitable for life. The 100% certainty by one scientist is ludicrous wishful thinking. If two planets have life an atheist scientist will say, there goes God and a privileged Earth. To understand what a life-giving planet must be like read both 'Real Earth' and 'Privileged Planet'.-http://www.foxnews.com/scitech/2010/09/29/odds-life-newfound-earth-size-planet-percent-astronomer-say/?test=latestnews