A Blog by

Look Up! There’s an Invisible Zombie Highway Right Above You

Step outside on a clear day this summer and look up.

What do you see? Blue. Nothing more. Or so you think.

But surprise! In July and August, an enormous herd of animals is passing directly over our heads. There are so many creatures up there, creatures that are so busy, so athletic, so tiny, so invisible. I’m talking about three to six billion of them every month soaring through the air directly above us. You should meet them. They are insects. High-flying insects. When I read about them in a science paper five years ago (I was at NPR at the time), I made this video, which provides a short introduction:

And now for the update.

It turns out, as you just saw, that the highest flying insect made it to 19,000 feet above sea level. That’s almost the height of Mount McKinley in Alaska. But more recently scientists have found another, even higher zone that’s also home to live critters that soar way, way up—miles higher, to the upper edge of the Earth’s atmosphere.

They are Earthlings that spend days, even weeks, practically in outer space.

What Are They?

According to David J. Smith and his team at the University of Washington and Kostas Konstantinidis and his team at Georgia Tech, there are thousands of species of very small, simple Earth life—bacteria, fungi, viruses—that get swept up by storms and make it to where there’s hardly any oxygen, where the temperatures are fiercely cold, and where they’re no longer protected from solar radiation by the Earth’s ozone layer.

And yet, write Peter Ward and Joe Kirschvink in their new book A New History of Life, most of these microbes will eventually come back down to Earth no worse for wear. They’re teeny. You can’t see them without a microscope. Typically, it would take almost 40,000 of them laid end to end to make it around your thumb.

Drawing by Robert Krulwich
Drawing by Robert Krulwich
Drawing by Robert Krulwich

But there are lots of them up there, so many that Ward and Kirschvink say this zone is becoming “the most newly discovered ecosystem on Earth,” a vast territory (many, many times greater than our oceans) where microbes routinely spend time dancing in the air.

Drawing by Robert Krulwich
Drawing by Robert Krulwich
Drawing by Robert Krulwich

Some bacteria have been in this high zone so regularly or for so long that they’ve adapted to life in the sky. Some species develop pigments that mimic sunscreen; some, says the New York Times, feed only on cloud water; and some can reproduce within clouds.

Drawing by Robert Krulwich
Drawing by Robert Krulwich
Drawing by Robert Krulwich

Scientists call this new family of creatures-in-the-sky “high life,” and it is a biological zone with its own rules. Up there is not like down here.

How Do They Survive Up There?

For one thing, scientists differ about how microbes at the upper end of the zone stay alive. When deoxygenated and freezing, do they slow way, way down like a hibernating bear? Or do they go dormant and essentially suspend their lives until they return? Or, as Ward and Kirschvink suggest, do they spend a brief period being dead?

Whaaaat?

This is one of the most provocative passages in Ward and Kirschvink’s book. “Most of us would agree,” they write, “that for mammals, and perhaps all animals, dead is dead.” You don’t come back from “dead.” But then they go on:

“… in simpler life, such is not the case. It turns out that there is a vast new place to be explored between our traditional understanding of what is alive and what is not.”

What if, in this new airy realm high above the planet, there could be “a place in between,” where bacteria might take wing, arrive in that freezing, irradiated zone, lose their life-giving machinery, and then, somehow, on the trip back down, build it back again?

Ward and Kirschvink are both well-respected senior scientists. Ward studies mass extinctions, Kirschvink magnetofossils. Neither is given to overstatement, which is why when I hit this line in their book, I put down my copy, stared out the window and thought, What?

How can anything be undead?

In the chapter I was reading, Ward and Kirschvink explore how life came to be four billion years ago. They suggest that instead of a single Genesis-like event (a bag of inert chemicals suddenly sparks into living chemistry), maybe “in the beginning,” chemistry switched back and forth, sometimes alive (on), sometimes not (off), and maybe, just maybe, in the simplest creatures, this may still be a habit—in fact, it may be happening to this day. Very simple creatures high in the sky, they say, might be alive, then not, then alive again, or as they put it:

“Life, simple life at least, is not always alive.”

Woah! This is a new idea to me. I tried to talk more with Peter Ward, but he’s in Papua New Guinea doing ocean research in a dugout canoe and doesn’t have a good internet connection, and Kirschvink is not answering email at Caltech, where he teaches. But I’m curious: Have any of you readers bumped into this notion? Life de-animating, then reanimating? It seems wonderfully preposterous—and very intriguing.

Let me know …


Peter Ward and Joe Kirschvinck’s new book “A New History of Life: The Radical New Discoveries About the Origins and Evolution of Life on Earth” goes after the hardest questions in life’s history, how did we begin, how simple life grew more complex, the origin of sex; they attack these puzzles carefully, feasting on the latest and especially the wildest research, so if you want an up-to-date primer guaranteed to keep your inner-college-sophomore up all night arguing, binging on ideas, going “no way”—this is a pretty good book. I also relied on David Montgomery and Anne Bikle’s “The Hidden Half of Nature, The Microbial Roots of Life and Health,” to get my head around itty bitty bits of life, the fungi, the bacteria, the archaea, the viruses, the protists. Their book took me into intestines, soil, and, yes, to the sky. It comes out in November. Also, my artist for the video, Benjamin Arthur, is about the most elegant, sly, multi-talented illustrator around; give him a tale, he’ll give you a perfect look to tell it with. Each of our ventures has a completely different visual style. Check out Why Can’t We Walk Straight? Last year he even turned in a piece (not with me, alas) on microbes. You can find it here.

Editor’s Note: This post has been updated to correctly reflect the spelling of Anne Bikle’s name.

10 thoughts on “Look Up! There’s an Invisible Zombie Highway Right Above You

  1. I love that there is life 19,000 feet above the earth feeding on cloud water. They are our planet’s welcome committee, welcoming the sun rays and any other intergalactic travelers.

  2. A new way to check for “life” on Mars! (Try on Earth first)
    Skip and Dip: Spacecraft skips off martian atmosphere at shallow angle while collecting samples in aerogel trays. Return to Earth for electron microscope study.
    You heard it here first! 😉

  3. Viruses do this all the time, they lie at the border of the living abd non-living. A virus is technically alive only when it finds a host.

  4. I am not surprised one bit that the microbial world is as wiley as Ward and Kirschvink suggest. “Alive” and “dead” are notions we have developed to help us make sense of the natural world. They work well most of the time, but not all the time. And as starrygordon points out, what are to make of the upstart viruses that straddle our definitions?

    In doing the research for “The Hidden Half of Nature” (btw I am “Anne”, not “Danne” 😉 my co-author and I ran into repeated instances of microbes squirming out of whatever shaped hole someone had tried to cram them in. Just when we thought we had a particular fact nailed down, it would pop up and we would sit down. Time for a re-write.

  5. Ice fishermen regularly toss the fish out on the ice to freeze solid. At the end of the day they collect the frozen fish and put them in a bucket of water to thaw before filleting them. The fish come back to life and swim around in the bucket. I would say that a fish frozen as stiff as a Popsicle isn’t “alive” before it thaws. This seems much more amazing than a frozen and desiccated bacterium or fungi, many of which can sporulate. Do you consider a spore to be alive?

  6. So our little tardigrade is not alone? Did he learn his tricks in this high life cycle?

    On another tangent, meningitis cases spike when rains finally fall after dry spells. Are similar, sporadic diseases tied to the cycle of high-flying viruses and bacteria? I believe Rambo Benson’s call for a terrestrial Skip & Dip could boost medical research.

Leave a Reply

Your email address will not be published. Required fields are marked *