Thursday, June 17, 2010

Aliens Within Us

(Warning: If you're more than normally squicked by multi-legged creatures, read no further.)

Have you heard of eyelash mites? Official name "Demodex folliculorum," they have a lifespan of 14 to 18 days, measure between 0.3 and 0.4 millimeters in length (visible only under high magnification), and live in human hair follicles. About one-third of all children, half of adults, and two-thirds of elderly people harbor eyelash mites. They're usually harmless. In fact, they perform a useful job, cleaning up fluids and dead skin cells that might otherwise cause pores to clog.

Here's a page with pictures. (Look at your own risk.):

Eyelash Mites

These tiny "bugs" are only one of the myriads of creatures that inhabit our bodies. Between 500 and 1000 species of bacteria live in the human digestive system. Some of them serve vital functions, while most have no effect on our health at all; they just find our entrails a suitable habitat, I guess. A similar number live on our skin, and human beings also host "microflora" in the mouth, nose, vagina, etc. (If a woman's vaginal ecosystem gets temporarily disrupted by antibiotics, she becomes more susceptible to yeast infections. So be thankful to your bacteria.) It's estimated that the human body contains at least ten times as many bacteria as human cells. We're a minority inside our own flesh!

This fact, by the way, undermines any assumption that intelligent extraterrestrials living on Earth-like planets will necessarily be humanoid. Not only do we share our external environment with thousands of animal species whose appearance and physiology differ from ours, millions of nonhumanoids happily inhabit our own bodies, and you couldn't get a much more compatible environment than that. (Still, I'd rather read and write about aliens who resemble us closely enough to have relationships with, so I'm happy to fall back on convergent evolution to justify human-sized and -shaped ETs.)

In Madeleine L'Engle's A WIND IN THE DOOR (the first sequel to her award-winning A WRINKLE IN TIME), heroine Meg becomes sub-microscopic and goes on an expedition into one of her sick little brother's cells to save his life. She meets a mouselike creature who lives inside one of his mitochondria. To this being, Meg's brother is not a person but a galaxy. Consider the millions and millions of living things for which each of us comprises the entire known universe.

This image brings to mind the opposite end of the scale, with the idea that our galaxy might be a sentient being. If it were, how would we know? Would a galactic mind, for that matter, have any notion that we're conscious and intelligent? Would any communication be possible? If our bodies' inhabitants included intelligent creatures like the nano-scale entities in A WIND IN THE DOOR, could we ever become aware of them or vice versa? And suppose one of them had a mystical revelation of its host "galaxy" as a sentient person. If that sub-microscopic prophet tried to share its insight with its companions, they might consider the "humanity hypothesis" as wacky as our mainstream culture considers the "Gaea hypothesis" (the idea that the Earth is a vast living organism).

When Walt Whitman wrote, "I am large, I contain multitudes," he probably had no idea he was stating fact, not metaphor.

Margaret L. Carter
Carter's Crypt

1 comment:

  1. It's really spooky when you post something I've been thinking about lately -- the human body as a habitat.