by Bob Berman
But random actions and probability theory remain a big part of the public’s “take” on natural motion. “Chance” is a key aspect of movement to which Aristotle and others gave careful attention. It supposedly has vast powers once it functions freely for long time periods.
So, seriously, could a million diligent, dedicated monkeys sitting at a million keyboards for a million years truly create the great works of literature, as is claimed? Believe it or not, such a problem is entirely solvable. Now, keyboards offer a lot of places to push; there are fifty-eight keys, even on old-fashioned typewriters. And 105 or so keys on most modern keyboards. When talking about random events, consider the difficulty of creating merely the fifteen opening letters and spaces of Moby-Dick: “Call me Ishmael.” How many random tries would be needed?
Given fifty-eight possible keys, the number of attempts would have to be 58 × 58 fifteen times over, which is three trillion trillion, before success could be expected. With a million never-sleeping monkeys working, all faultlessly typing sixty words a minute (so that typing fifteen keystrokes takes just four seconds), one of them would indeed eventually type “Call me Ishmael.”
But odds are it would take thirty-eight trillion years. Three thousand times the age of the universe.
So a million monkeys typing furiously would never even reproduce one book’s single short opening sentence. Bottom line: randomness has far less power to achieve results than is popularly imagined.
One other ultrafast superluminal phenomenon may also exist. This one is independent of Copenhagen. In theory, if and when the big bang created the observable universe, it could also have created a cosmos of tachyons—faster-than-light particles. At least it’s allowable by math and physics. That’s because, although nothing with any mass can ever reach light speed, there is a major escape clause. Namely, the speed limit only applies to objects being accelerated—objects that start off slower than light. For them, attaining 186,282 miles a second is a hopeless quest.
But what if, at the universe’s birth, there was a realm of objects that went faster than light from the get-go? These tachyons—whose name was coined only in 1967—are permitted by science. For them, the light-speed barrier remains, but they’re trapped on the other side. They can never slow down to light speed!
It takes just as much energy to slow down as to speed up. So tachyons would presumably grow heavier and have their time increasingly distorted as they tried to decelerate to light speed.
Like us, they could never cross that barrier. We could never see each other, since photons would never travel from them to us or vice versa. Thus any search for tachyons is a hunt for the invisible.
All this is mentioned only because a study of motion should include a consideration of the fastest conceivable objects. In theory, we should be able to detect the effects of tachyons; they ought to influence cosmic ray showers (also called air showers) and emit detectable blue Cerenkov radiation when they lose energy. Such studies have always come up empty. Few if any physicists believe they exist, even if they remain a sci-fi staple.
So we can probably cross tachyons off the list of things that move. It seems there will be no way to break the photon barrier. Faster than light is out.
Only infinity gets the nod.
CHAPTER 18: Sleepy Village in an Exploding Universe
Back Where It All Began
Up a lazy river, how happy we will be
Up a lazy river with me.
—HOAGY CARMICHAEL AND SIDNEY ARODIN, “LAZY RIVER” (1930)
The odyssey was over, and I was back in my repaired home. My never-changing village of two hundred people had not stirred while I was gone. Even the annoying, omnipresent, garden-destroying deer seemed the same, albeit with a few new fawns to carry on the tradition. China may be speedily changing, but you’d have to look long and hard to see anything very different in rural upstate New York during the past forty years I’ve lived here. Brenda at the post office smiled as she handed me a huge pile of mail, bundled with rubber bands.
My desk and its vicinity were littered with their own explosions of spiral-bound notebooks and loose papers and scribbled interviews. It was wrap-up time. I grabbed the phone to cross-examine the Carnegie Observatories astrophysicist who had promised me results from my night on that mountain in Chile so long ago.
He kept his word. Dan Kelson—still upbeat if a bit disheveled, thanks to his two small kids running around and around his office—was effusive with excitement. The four thousand galaxies he personally measured that night, along with his follow-up observations, had revealed places where cities of stars fly away from us at an impressive percentage of light speed. The measurements had carried him to the strange barrier beyond which humans can never see: the edges of the observable universe.
We were both excited about even newer data. In 2013, he had made world headlines by finding the fastest and farthest galaxy ever. And I had just spoken with Shirley Ho, part of the team from Lawrence Berkeley National Laboratory that in 2012 had finished measuring data from an astonishing nine hundred thousand galaxies. They’d used sound waves propagating through the younger, denser cosmos—called baryon acoustic oscillations—to gain groundbreaking information, which these days pours in at a rate previously seen only in science fiction movies.
“They show, without a doubt,” she’d said to me, “that space has a flat topology.”
Dan Kelson and I now discussed this with excitement. You see, if the entire expanding universe is finite, with a specific limited inventory of stars and galaxies and energy, it would warp space itself. Light traveling long distances would gradually curve. But this new data supports Carnegie’s previous findings: light doesn’t curve. It travels in laser-straight lines. On the largest scales, space has a flat topology.
This strongly suggests an infinite universe. That there’s no end to the galaxies. And—back to motion—that speeds just keep getting faster and faster the farther you look, without any terminal point.
We already observe galaxies that are essentially flying away at the speed of light. And of course we’re observing them as they were in the distant past, nearly thirteen billion years ago, when their light started out on their long journey to our eyes. Projecting where they must be today, we conclude that they are currently zooming away far faster than light speed.
And it just keeps going. How can anyone comprehend this?1
I asked the president of the American Astronomical Society, Debra Elmegreen.
“Yes, we may indeed have a flat topology and an infinite universe,” she acknowledged, echoing what Shirley Ho had said a week earlier. “But even if we can only observe a tiny fraction of the whole thing, that still amounts to two hundred billion galaxies. It’s quite enough to keep us busy.”
No doubt. But she slightly misspoke. “Infinite” space doesn’t mean “very large.” It doesn’t mean that everything we observe is “a tiny fraction” of the actual universe. Any percentage of infinity is zero. So all we can ever observe is zero percent of the cosmos.
I felt like Alice, endlessly tumbling. Can it be that the entire tapestry we observe is not even a few brushstrokes of the entire cosmic masterpiece? I contacted Caltech theoretical physicist Sean Carroll, who cautiously said that while our observations would be able to prove a finite universe if it existed, you can never prove infinity. Nonetheless, given the current data, he believes that “the universe probably is infinite.”
What does that mean regarding cosmic motion and everything else? Well, he said, “either an infinite number of different things happen or a finite number of things happen an infinite number of times. Either of those possibilities is pretty mind-boggling.”
An infinite universe—the increasingly likely reality—also means that the most energetic motion event of which we’re aware, the big bang, was probably just a local happening, a big to-do in the ’hood, confined to the observable universe. As for the larger universe beyond, no one can do more than speculate. Does it simply exist foreve
r? Did it “start” smaller and, thanks to the mysterious dark energy that continuously inflates its expansion rate, ultimately grow into what will become infinite size? If one had to bet the farm on it, smart money would wager that the cosmos never even had a birth. Which means Aristotle was right: we’re part of an eternal entity.
I phoned University of Chicago cosmologist Rocky Kolb to get his take on all this. He just chuckled. An infinite universe, he said, would have “started out everywhere at once, as infinite from the beginning.”
He confirmed that, given the likelihood of infinity, the speed of receding stars and galaxies is limitless. For simplicity’s sake let’s call everything we can observe, to a distance of thirteen billion light-years, “one universe,” or 1 u. Infinite expansion, in which speeds increase exponentially with distance, as we’re already observing, means that at some faraway location galaxies currently increase their separation from us by one universe per second. Call it 1 ups.
We created our original units of measurement based on human experience. A foot was very nearly the length of a man’s shoe, a yard was a long step. A mile was how far a person walks in twenty minutes. Even by these clumsy standards, we are able to state—and perhaps even grasp—that the most distant observed galaxies are something like 170,000 miles farther away from us each second.
But unseen multitudes growing one universe farther away per second? And, say astrophysicists, who grasp that the visible cosmos is barely the iceberg’s tip of all that exists, this still isn’t the end. There must be far more galaxies zooming at the speed of one million ups. One million universes per second. And that’s not the end, either.
We’ve seen the lower terminus of speed. It’s absolute zero, where even atoms stop moving except for some subtle quantum effects. You can’t go any slower than stopped. But the upper limit, long thought to be light speed, has now been penetrated with a vengeance. The gap between ourselves and those unobservable distant galaxies grows in ways we can never visualize because nobody can picture infinite speed. Exploring cosmology is starting to resemble the medieval study of magic. There’s no answer to it.
Is that the last word? Ever-increasing accelerations of limitless objects? All of which are forever unobservable? Fathomless oceans of mysterious entities whose mere contemplation is an encyclopedia of futility? What do we do with this? Should we feel titillated or suicidal?
Happily, there’s a catch. Physics shows us that space itself may be real on some levels but not others. Maybe there’s something fishy about all this distance and velocity in ways our science has yet to fully grasp. Looking at millennia of cataclysmic changes, of bedrock certainties overthrown even in our lifetimes, we see that virtually everything we now know about movement through the cosmos seems alterable.2
“All scientific theories are models of nature based on observation,” explained my friend Tarun Biswas, a relativist and physics professor at the State University of New York. “The problem with cosmology is that its current model is based on negligible observational data. It would still not be a problem if people did not take it so seriously—if they understood that it is only a starter model.” If we can remember that we are still taking our first baby steps in visualizing the cosmos and its contents and its motions, we may be less frustrated by the mad superluminal recession at its fringes.
The fastest speeds, remember, are not those of material objects being accelerated but that of the empty space expanding between us and them. The modern physics chronicle has a certain disconcerting quality: in the quantum phenomenon of tunneling, objects pass through supposedly impenetrable barriers and blithely materialize on the other side. And in the particle entanglement we explored in the previous chapter, something—some knowledge or influence or unknown entity—penetrates unlimited depths of space in zero time. All these suggest that space is a funny thing, with travel possibilities we are only beginning to understand.
We’ve come a long way since Galileo sent metal balls rolling down ramps. We’ve explored the speeds and vagaries of nearly every kind of object in all areas of nature. As for these superluminal galaxies exceeding the limits of our understanding, well, such off-the-scale speeds numb the mind today, but—count on it—they will mean something else to our grandchildren.
A sudden breeze blew the curtain on my office window inward, knocking over a vase overfilled with dried flowers. I swallowed an oath before it even moved past my lips, my eyes drawn to the blowing branches outside the window. Was that you, Torricelli, conjuring some sort of closing statement?
Silly thoughts. I shook them off.
After all, it’s looking more and more like Aristotle and Alhazen were right: motion never began.
There can be no final curtain.
Acknowledgments
My thanks to Jane Weinberg for her invaluable help. And to my editors, John Parsley and Barbara Clark, who made everything better.
About the Author
BOB BERMAN, one of America’s top astronomy writers, contributed the popular “Night Watchman” column to Discover for seventeen years. He is the author of The Sun’s Heartbeat and is currently a columnist for Astronomy, a host on Northeast Public Radio, and the science editor of the Old Farmer’s Almanac. He lives in Willow, New York.
ALSO BY BOB BERMAN
The Sun’s Heartbeat
Biocentrism (with Robert Lanza, MD)
Shooting for the Moon
Strange Universe
Cosmic Adventure
Secrets of the Night Sky
APPENDIX 1
Table of Selected Natural Speeds
VERY SLOW (NOT VISUALLY DISCERNIBLE)
Stalactites 1 inch / 500 years
Tectonic plates 1–4 inches / year
Mountains 1/7 inch–2.4 inches / year
Sea level (twenty-first century) 2 inches / decade
Toenails 1/2 inch / year
Fingernails 1/8 inch / month
Hair 1/2 inch / month
Trees 1–2 inches / month
Fastest-growing plant (bamboo) 1 inch / hour
Bacteria (typical) 6 inches / hour
Germs (fastest) 1 foot / hour
Undisturbed airborne dust 1 inch / hour
Sperm 1 inch / 4 minutes
Snails (typical) 1 inch / 50 seconds
SLOW BUT VISIBLE
Snails (fastest) 40 feet / hour
Sloths 2 inches–1.7 feet / second
Ants 0.20 miles / hour
Giant tortoises 0.23 miles / hour
VISIBLE
Rivers 3 miles / hour
Human swimmer (fastest) 4–5 miles / hour
Drizzle (salt-grain-size rain) 4–5 miles / hour
Large raindrops (house-fly-size) 22 miles / hour
Cumulus clouds (typical) 20–30 miles / hour
Sharks 30 miles / hour
Greyhounds 45 miles / hour
Ocean waves 45 miles / hour
Fastest land animal (cheetah) 60–70 miles / hour
Large hailstones 105 miles / hour
Meteorite striking rooftop 250 miles / hour
Tsunami at sea 500 miles / hour
SUPERSONIC
Sound through air (thunder) 1/5 mile / second
Earthquake waves 5 miles / second
Earth around sun 18.5 miles / second
Meteoroid entering Earth’s atmosphere 5–40 miles / second
Sun and Earth around galaxy center 140 miles /second
Solar wind particles 300 miles / second
Light through glass 139,600 miles / second
Light through space 186,282.4 miles / second
All are consensus or average values.
APPENDIX 2
A Note on Accuracy and Choice of Units
In a number of cases, authoritative sources cite conflicting information. How fast does Mount Everest rise annually? Some say 3.9 inches, others say 0.15 inch. I have contacted three university geology professors and received conflicting information even from them! What’s the top sp
eed of a sloth? Seemingly reputable sources cite figures that range from one hundred feet a minute to five feet a minute. In such cases of wild disagreement I have included the range of accepted data. In others, where the disagreement was smaller, I have simply listed the average.
While nearly all the world, including the entire science community, exclusively employs metric units, this book mostly expresses itself in US or Imperial units. The choice was deliberate and the reason simple: for the vast majority of Americans as well as many in Great Britain, the content will be more meaningful if expressed in familiar terms. For example, when we reveal the speed of falling rain, few would find “9.8 meters per second” as clear and meaningful as “twenty-two miles per hour.”
Bibliography
The data in this book come from hundreds of sources. For example, a single sentence about the respective growth rates of willow trees and maple trees comes from a poster for homeowners published by a Florida utility company, which obtained the information from the Arbor Day Foundation. For this bibliography, the twenty-one data resources listed below contain trustworthy, meaty content for follow-up explorations.
Books
Bagnold, R. A. The Physics of Blown Sand and Desert Dunes. Mineola, N.Y.: Dover Publications, 2005.
Bova, Ben. The Story of Light. Naperville, Ill.: Sourcebooks, 2001.
Considine, Glenn D., ed. Van Nostrand’s Scientific Encyclopedia. 9th ed. 2 vols. Hoboken, N.J.: Wiley-Interscience, 2002.
Gosnell, Mariana. Ice: The Nature, the History, and the Uses of an Astonishing Substance. New York: Alfred A. Knopf, 2005.
Leonardo da Vinci. The Notebooks of Leonardo da Vinci. Edited by Edward MacCurdy. Old Saybrook, Conn.: Konecky & Konecky, 2003.