Are we alone in the universe?

For the longest time, belief in extraterrestrial life was considered a fringe viewpoint, more suitable for sci-fi conventions and fans of Star Trek or the X-Files. Today, it’s the exact opposite. Those who reject the notion of alien life are considered to be the outliers. This change in attitude occurred for several reasons, perhaps none as important as the discovery that exoplanets are everywhere — 100 billion of them in the Milky Way galaxy alone. Surely, with so many opportunities for life to flourish, the universe must be teeming with extraterrestrials. But is it? Other than Earth, there’s almost certainly no other life in our solar system. Most exoplanets we know of are not particularly hospitable to life. Most stars are incapable of supporting photosynthesis. The reality is that Earth-like planets are probably rare, but that doesn’t rule out E.T. The universe, after all, is a pretty big place. The debate continues.