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How Alien Can a Spacefarer Be?

As our planet makes more and more noise, we can’t help but wonder why no one is paying attention. Are we alone in the universe? Or alone in our desire to discover new worlds? PZ Myers says “Spaceship building is never going to be a selectively advantageous feature — it’s only going to emerge as a spandrel, which might lead to a species that can occupy a novel niche.” Humanity could tread that path, following our dreams to the stars. But even then, we might only find extraterrestrials in the form of well-adjusted slime blobs, content in their otherworldly ecosystems.

If there are other tech-savvy lifeforms in the galaxy, would they communicate with lasers instead of radio waves? This could explain our apparent isolation, because the civilized worlds are narrow-beaming communications to their neighbors and leaving us in the dark. Chad Orzel explains how it would work, with a possible assist from a ‘magic compact fusion reactor.’ That device is still on our to-do list.

Comments

  1. #1 G
    July 16, 2014

    Yes, yes, and no.

    Yes they are probably using lasers between their various inhabited worlds (or they’ve invented the Ansible;-), because ordinary RF is terribly inefficient at interstellar distances.

    Yes they are probably ignoring us, or perhaps they’re still deciding if we’re too dangerous to contact.

    But no, I’ll have to differ with PZ about selection utility.

    Compared to the estimated future lifespan of the observable universe, Earth life is barely in its infancy. Any life-bearing planet will eventually face extinction as a function of the life cycle of its home star. For example in approx. 1/2 billion years, the Sun’s luminosity will increase to the point where Earth’s carbon cycle is disrupted and the oceans boil. Nothing will survive that except possibly some isolated extremophile bacteria.

    But if we succeed in becoming an interstellar civilization, the lineage of Earth life will continue beyond the loss of Earth itself. Having made the jump to a new star system once, we will be able to keep doing it until Earth-originated life inhabits a number of other planets in our region of the galaxy.

    The more planets we occupy, the more resilient we are against the loss of any of those planets.

    The mechanisms are the same as applied when humans spread from Africa to the rest of the globe: any local catastrophe might take out a subset of the whole, but the species would continue.

    That is a selection advantage, in the same manner as building canoes and sailing ships was a selection advantage in the past.

    The fact that Earth-originated life will diverge in various ways over time, does not invalidate the premise.

    This is Darwinian selection on the cosmic scale, over a span of potentially trillions of years.