Semi to intelligent life exists on other planets.

(I had written a lot, and then my page refreshed on me and all was delete :(... ) Anyways, firstly I disagree with your view that in order for me to win this debate, I have to show proof that life exists on another planet. This would just be a show and tell of facts (and obviously this has not been proven yet so I would've lost this debate straightaway), rather, in order for me to win, I must provide and present information that IS available, and justify it in a way that allows readers to believe my side. Secondly, by semi to intelligent life, I meant those above the single celled bacteria and plants. Many scientists and others believe that in order for life to be present, water is a central force. While this may or may not be true (we tend to base the success of life on Earth on things that WE thrive on. Aliens may or may not have to live under our ecosystem/environmental standards. (More on this soon.) Mars once had water on the planet (as shown on http://www.sciencedaily.com...). The fact that a planet right next door once had water already shows the possibilities of many more planets thriving with water. Again, this is all based on possibilities (however, my side of the debate can only be based on probability and luck etc.) Another reason to believe that aliens do not have to thrive in an environment that mimics Earth's, is the different environments that the multitude of animals live in. Fish who live in the extreme depths of the ocean experience a much different sense of pressure as land-dwellers. Just because humans are unable to go down to these depths without equipment doesn't mean that animals do not live down there. To add to this, antarctica, a continent on earth experiences periods of time where days can last 24 hours or near and vice versa. This is not to say that life doesn't exist there (penguins, seabirds to name a couple. (http://library.thinkquest.org...). In addition, you say that the Homo genus is estimated to be about 2.3 million years old, which is only 0.05% of earths existence. This is true. However, the homo genus is not the only semi to intelligent forms of life. Anything from a cockroach - which has existed for over 350 million years - to the dinosaurs etc. In addition to this, "The process of biological evolution was very slow at first. It took two and a half billion years, to evolve from the earliest cells to multi-cell animals, and another billion years to evolve through fish and reptiles, to mammals. But then evolution seemed to have speeded up. It only took about a hundred million years, to develop from the early mammals to us." (http://www.hawking.org.uk...). Lastly, half a billion years of semi to intelligent life is recorded to have existed on earth. This is about 1/10th of earths existence (and it should continue to flourish for many many years to come). The chance that another planet has existed with a sustainable ecosystem (for an alien, not necessarily for a human - as many an ignorant person has falsely believed) exists and according to Stephen Hawkings, is not necessarily difficult "But, the fact that several pulsars are observed to have planets suggests that a reasonable fraction of the hundred billion stars in our galaxy may also have planets. The necessary planetary conditions for our form of life may therefore have existed from about four billion years after the Big Bang." (Stephen Hawking http://www.hawking.org.uk...) The chances of life occurring on another planet is difficult, however extremely possible. The chances of life existing concurrently is smaller still, however is still extremely possible.