We are the only life in the universe its our duty to populate it we are the beginning or all life. To get the same conditions on another planet exactly like Earth is impossible even though the universe is infinite you cannot assume the qualities of space or the laws of the universe are constant. If you draw a mathematical universe based solely on the observations of our own known universe its impossible to measure any difference in such a small area. The Earth is unique! I also would love my idea / theory to be proven wrong.
If there were ever to be alien contact on earth it would probably be by machines.
That is the assumption that we are working under, however; and so far, every thing we see seems to be composed of the same elements, which does suggest the same physics and chemistry. IMHO it would be difficult to find a planet exactly like Earth, but I think it is extremely likely there are many very similar. Even if there is a 0.000000001% chance per star of having an Earth-like planet, there would still be about 10,000,000,000,000 of them in the observable universe. Also, we only have an example of life on our planet, it could actually be more likely on other types of planets. Probably no more likely, but even if it can happen on other planets, that only increases the odds.you cannot assume the qualities of space or the laws of the universe are constant.
when you say Earth like at what stage of earth's development are they talking about when they look for the signs of life? does this 0.000000001% chance account for the process earth has been through? or an assumption of the state of a current planet being similar to ours?