Thomas - A million years with you: a memoir of life observed

Copyright 2013 by Elizabeth Marshall Thomas

All rights reserved

For information about permission to reproduce selections from this book, write to Permissions, Houghton Mifflin Harcourt Publishing Company, 215 Park Avenue South, New York, New York 10003.

www.hmhbooks.com

Library of Congress Cataloging-in-Publication Data is available.

ISBN 978-0-547-76395-8

eISBN 978-0-547-76404-7
v1.0613

In loving memory of Pearl

I LIKE TO LOOK at the stars, so far away, so steady on their paths through the sky. Theyve been credited to Gaia, the goddess whose name means Earth and who is best known for managing our planet, orbiting a little star among 4 billion others in our galaxy. Even so, however small, our planet is complex and took 4.5 billion years to reach the state in which we know it, thanks to measures which were also credited to Gaia. Imagine it: The crashing meteors! The chemical reactions! The climate changes! The ever-branching climb of evolution that turned bacteria into blue whales and giant sequoias, not to mention the millions of other life forms that we know today! If she could do all that, could she not have made the stars and written the laws of physics? According to the ancient Greeks she could. She made the earth, then made the universe to be its equal.

While wandering down the road of life, it helps to look for something more meaningful than oneself. Some find it in religion. Some find it in relationships. I find it by keeping my eyes open. I see the stars when I look up and the soil when I look down, where the microorganisms live that keep everything going. And as far as Im concerned, this can be personified by Gaia.

One day my wonderful cousin, Tom Bryant, came to visit me and my husband, Steve, at our home in Peterborough, New Hampshire. Tom, an astronomer, was marvelously familiar with everything now known about the universe, and wishing to show us some of it, he brought a very large telescope. That night, after the moon set, a group of us went to the edge of a field where, in the northeastern sky, Tom pointed out what seemed to be a tiny, fuzzy star, just one among dozens of others, and not all of us were sure just which star we should be looking at. Tom then showed us the star through his telescope. This made it larger, about the size of a grass seed. It seemed to be a spiral and looked something like a snail seen from the rear.

It was part of Andromeda, Tom told us, a constellation of about four thousand stars, nine of which are known to have planets. But the tiny, snail-like thing we were looking at was not an individual star at all, and it wasnt a planet. It was a cluster of a trillion stars, collectively known as the Andromeda Galaxy, three times bigger than our Milky Way and closer to us than any other spiral galaxy. Its light had traveled for 2.5 million years before it reached us. When the light we saw that night left its galaxy, our Homo habilis ancestors were figuring out how to make stone tools. By the time that same light reached us, we were modern Homo sapiens with telescopes. Wow!

With my eyes on Andromeda that night, I remembered an experience Id had during my freshman year in college, where Id hoped to major in biology. My dad had given me a binocular microscope, through which I watched the little life forms in drops of water taken from a swamp. One day, as I was following what I took to be a paramecium moving carefully through the algae like a fox hunting mice in a field, an enormous creature suddenly loomed up and charged right at me, causing me to throw myself backward and tip over my chair. It took me a moment to realize that I was in my dormitory room and the terrifying creature was in the drop of water.

But what was it? I gathered my courage and looked again. It was not a protist, then called a protozoan. Instead, it was an animalvery small but an animal nevertheless. It had eight legs with claws, a face with a tiny snout, a mouth, and two eye spots, and a transparent body in which I could see its food as well as some oval shapes toward its hindquarters which I took to be eggs. Whatever it was, it seemed to be a female.

I consulted a textbook. She was a waterbear, a tardigrade, then believed to be a miniature relative of the mites. I was able to lift her up with the point of a sewing needle, and found, as I turned the needle from side to side, that she was just barely visible to my youthful naked eyes, and not visible at all if she was on the far side of the needle. She was that small. I put her in my jar of water so I could return her to the swamp.

Ever since then, Ive been enthralled by waterbears. I later found what superscientist Lynn Margulis wrote about them and learned what Id already suspected, that they are among the most amazing creatures on the planet. Their many species live in all kinds of places, from the deep ocean to the Himalayas, from hot springs to the Arctic, because they can survive extreme temperatures. Some live in water thats 304 Fahrenheit, and others live at just three degrees above absolute zero, the point at which all thermal energy is gone. In other words, since few places on earth are that hot or that cold, waterbears can flourish almost anywhere.

In fact, theres almost nothing they cant cope with. If a waterbear is injured or starved, it forms itself into a cyst, a tiny roundish lump, in which it contracts its little body and repairs itself. Most waterbears live in swamps or in damp mosses and all of them eat liquid foods, but if the liquid disappears, they form themselves into tuns, which look like tiny wine barrels. These tuns, like dust particles, ride the winds to faraway places which, with any luck, will be better than the places they left. And theres no special hurry to find a good place. In the form of a tun, a waterbear can live for about a hundred years.

And thats not all. Waterbears can survive 570,000 roentgens of radiation, when just 500 roentgens will sizzle one of us. Its hard to imagine how they evolved this astonishing ability or why they need it, as 570,000 roentgens might accompany a nuclear disaster but not much else. Waterbears had this ability before we invented the nuclear disaster. But when we did, they were prepared. They seemed to leave little to chance.

Perhaps for that reason, most waterbears are female. Without males, they lay eggs that hatch as females; thus just one she-waterbear could repopulate the planet if things went wrong. And evidently thats just what theyve been doing. Creatures so tiny dont often leave fossils, but a few were found in amber from the Cretaceous era, and a few others from the mid-Cambrian era. Long before our ancestors came out of the trees, waterbears were here.

On the day I watched the waterbear, I was listening to a radio on the table with the microscope. The music was quite loud, and I wondered what the waterbear made of the sound. I didnt see that she had ears, so I believed she couldnt hear it, although she might have felt vibrations. But these would tell her nothing about the radio itself, nothing about the broadcasting station or the instruments that played the music or the species that composed it, nothing about electricity or power lines or even the electric cord from the radio to the plug in the wall. Its hard to imagine all the things about a radio that my waterbear was not equipped to understand.

Then it came to me that as the waterbear was to the radio, so are we to the universe. For all the characteristics by which we place ourselves above the other life forms of this planetour language, tool use, and hind-leg walking (now more or less reduced to hind-leg walking, as language and tool use have been found in other species)were just another primate, and as such we have our limits. We think were smart, way ahead of waterbears, but 15 billion years ago there was no universe, and whatever started it might very well be something that our simian brains are not equipped to understand.