Supported by Supported by Protocol Labs Supported by Protocol Labs Follow your curiosity. Supported By Protocol Labs Follow your curiosity. Lead humanity forward. Protocol Labs Follow your curiosity. Lead humanity forward. Follow your curiosity. Lead humanity forward. "In all the universe, "In all the universe, there stands only one known tree of life." "Does it stand alone? "Does it stand alone? Or is it part of a vast cosmic wilderness?" "Imagine a museum containing every type of life in the universe." "What strange things would such a museum hold?" "What is possible under the laws of nature?" LIFE BEYOND CHAPTER II CHAPTER II THE MUSEUM OF ALIEN LIFE To have any hope of finding alien life, we have to know what to look for. But where do we begin? How do we narrow down a seemingly infinite set of possibilities? There's one thing we know for sure: nature will have to play by her own rules. No matter how strange alien life might be, is going to be limited by the same physical and chemical laws that we are. 6 CO2 + 12 H2O → C6H12O6 + 6 O2 On top of this, each alien environment will further limit what kinds of life forms can evolve there. Despite these natural boundaries, the possibilities are staggering to imagine. Trillions of planets, each a unique cauldron of chemicals, undergoing their own complex evolution. To guide our thinking, this museum of alien life will be divided into two exhibits: Life as we know it: home to beings with bio-chemistries like ours. And life as we don't know it: home to beings that challenge our concept of life itself. Before we venture too far into the unknown, we have to ask ourselves: what if alien life is more like ours than we think? EXHIBIT I EXHIBIT I LIFE AS WE KNOW IT EXHIBIT I LIFE AS WE KNOW IT CARBON & WATER BASED If there's one feature that unites us with these other specimes in this museum, it's carbon. Carbon is ubiquitous, it's one of the most common elements in the universe, and is very good at forming large stable molecules. Carbon has the rare ability to form four way bounds with other elements and to bind to itself in long, stable chains; enabling the formation of huge complex molecules. This versatility makes carbon the center piece in the moleculary machinery of life. And the same carbon compounds that we use have been found far from Earth, clinging to meteorites and floating in far off clouds of cosmic dust. The building blocks of life drifting like snow through the universe. And if alien life has selected other carbon compounds for the biochemistry, they will have plenty to choose from. Scientists recently identified over a million possible alternatives to DNA: all carbon based. If we ever discover other carbon based life forms, we will be fundamentally related. They will be our cosmic brother. But would they look anything like us? If they hail from Earth like planets, we could share even more in common, than just our biochemistry. What would life be like in another planets, if its evolved? Would it be like, the world today here on Earth? Or would be completely different? There are those, who argue that from the argument of convergent evolution, if conditions on other planets are similar to here, then we will see very similar life forms; animal and plant-like organisms, that look very familiar. On Earth, certain features like eyesight, echo-location and flight have evolved multiple times, independently, in different species. This process of convergent evolution could extend to alien planets like Earth, where creatures share similar environmental pressures. It's no guarantee, but there could be certain universalities of life; the greatest hits of evolution on repeat across the Universe. Each feature would be a tune to its local environment. Dimly lit planets would produce huge eyes to suck in extra light, like nocturnal mammals.