The search for extraterrestrial life focuses on "chemical disequilibrium." The simultaneous presence of oxygen and methane in an exoplanet's atmosphere would be a strong indicator of life, as they naturally destroy each other, implying a constant biological source is replenishing them.
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The Fermi Paradox—where are the aliens?—can be explained by the "Great Filter" theory. Astrophysicist Alex Filippenko believes this filter is likely in our future, meaning civilizations like ours often destroy themselves before colonizing the galaxy.
The success of iterative design processes hinges entirely on the metric being measured. An enzyme evolved for temperature stability won't necessarily remove clothing stains unless stain removal is the specific property being screened for. This highlights the critical importance of defining the right success metric from the start.
Beyond being an alternative fuel source, the ketone body beta-hydroxybutyrate (BHB) functions as a signaling molecule. It acts as an HDAC inhibitor, which can activate genes that enhance the body's antioxidant and cellular defense mechanisms, a pathway of interest in cancer therapy.
The Fermi Paradox asks why we see no evidence of alien life. A compelling answer is that any civilization with technology for interstellar travel would have already developed superior virtual realities. Exploring infinite digital worlds is safer, cheaper, and more efficient than physical travel, making it the logical path for advanced species.
With directed evolution, scientists find a mutated enzyme that works without knowing why. Even with the "answer"—the exact genetic changes—the complexity of protein interactions makes it incredibly difficult to reverse-engineer the underlying mechanism. The solution often precedes the understanding.
The force of gravity is precisely tuned for life to exist. If it were slightly weaker, stars wouldn't ignite; slightly stronger, the universe would have collapsed. This 'Goldilocks' condition is so improbable that some scientists argue it suggests our universe is just one of many, most of which are sterile.
Current LLMs fail at science because they lack the ability to iterate. True scientific inquiry is a loop: form a hypothesis, conduct an experiment, analyze the result (even if incorrect), and refine. AI needs this same iterative capability with the real world to make genuine discoveries.
The reason we don't see aliens (the Fermi Paradox) is not because they are distant, but because our spacetime interface is designed to filter out the overwhelming reality of other conscious agents. The "headset" hides most of reality to make it manageable, meaning the search for physical extraterrestrial life is fundamentally limited.
A novel answer to the Fermi Paradox (why we haven't met aliens) is that any sufficiently advanced civilization inevitably finds creating infinite, engaging virtual worlds more compelling and energy-efficient than interstellar travel. AI is the technology that will lead humanity down this same path of virtual exploration.
Beyond optimizing existing biological functions, Frances Arnold's lab uses directed evolution to create enzymes for entirely new chemical reactions, like forming carbon-silicon bonds. This demonstrates that life's chemical toolkit is a small subset of what's possible, opening up a vast "non-natural" chemical universe.