Charles S. Cockell:
And, yes, our own form is also shaped by these rules. Our eyes, which let us see by collecting electromagnetic radiation, work according to the same principles that we use to build cameras: Lens and iris work together to focus and control the light. Evolution has sculpted our bones to a thickness that is just right to hold us fast against the ever-present gravity of the Earth, yet not so heavy as to weigh us down. Our upright posture, with limbs free to build tools and manipulate the world using the powerful computer in our skulls, is a hallmark of physics.
Aliens, if we ever meet them, are unlikely to be copies of us. Their multifarious organs and limbs—nothing in physics says that they must have two legs and two arms in the same places as us—may be arranged in different ways. But they, too, will bear the indelible imprint of the laws of physics, which work their way through everything in the universe, from a worm to a wormhole. Creatures akin to E.T. and Yoda are more likely than sentient blobs as our interplanetary neighbors.
One easy critique of science fiction (certainly in television and film) has been how most aliens seem awfully human-like. In the old days, that was obviously because humans had to play said aliens. But what if the laws of science do in fact dictate aliens be more human-like than not?Read more...