Given that we now know that planets are common, that many of them are found within their stars’ habitable zones, and that organic materials are common in the Universe, there ought to be many places that are suitable for life. But even under the right circumstances, we don’t yet know how likely it is for life to originate. The Anthropic Principle states that we, as living, conscious observers, must necessarily find ourselves in a place with conditions suitable for life, or else we wouldn’t be here to observe those conditions. In other words, having already won the “life lottery”, it’s unsurprising to find ourselves in possession of a winning ticket. We don’t yet know, though, how many other winners there are, how many players didn’t win, and what the odds are in the game. Scientists are endeavoring to obtain better statistics to help us answer these questions.
Another interesting question is whether intelligent life is likely to evolve once life itself has originated. Although single-celled organisms arose quite quickly on Earth, it took another 2.5 billion years for their descendants to evolve into multicellular organisms and a further billion years for advanced intelligence and the development of communication technologies to arise. With only one example to study at the moment, we don’t know if this process is inevitable or if intelligent life is rare.