by Ziya Tong
We can count ourselves lucky today that there aren’t dog-sized cockroaches scuttling through our kitchens. That’s because insect gigantism came to an end when another animal rose to prominence. One hundred and fifty million years ago, dinosaurs evolved into a new kind of flying predator: birds. For insects trying to make a quick getaway, the slight and streamlined among them fared better than the big and bulky. Evolution favoured a smaller body size for escape, and insects began to shrink.*21
The size of a species is not accidental. It’s a fine-tuned interaction—a back and forth—between a species and the world it inhabits. Over large periods of time, size fluctuations, from dwarfism to gigantism, have often signalled significant changes in the environment. Generally speaking, however, over the last five hundred million years, the trend has been towards animals getting larger. It’s particularly notable in marine animals, whose mean body size has increased 150-fold in this time.*22
But we are beginning to see big changes again. Scientists have discovered that many animals are shrinking.*23 Around the world, species in every category—fish, bird, amphibian, reptile, and mammal—have been found to be getting smaller, and one key culprit appears to be the heat.*24 Animals living in the Italian Alps, for example, have seen temperatures rise by three to four degrees Celsius since the 1980s. There, even at an altitude of one thousand metres, heat waves have spiked the alpine temperatures to as high as 30°C. To avoid overheating, chamois goats now spend more of their days resting rather than foraging, and as a result, in just a few decades, the new generations of chamois are 25 percent smaller, and are dwarfs by comparison. Underwater too, sea temperatures have begun to rise, one consequence of which is that the water holds less oxygen and becomes more anoxic. Scientists studying six hundred species of fish say that big size changes are coming and that by 2050 fish will have shrunk by as much as a quarter.
Shrinking potentially signals an even bigger problem: a population crash. Looking at commercial whaling data over four decades, researchers documented that sperm whales shrank substantially—by four to five metres—in the years before their populations collapsed. For biologists, then, shrinking is like an early warning system, alerting us that a species may be in trouble.
But not all animals are shrinking. Domestic species that we raise for food, like pigs and cows, for instance, are growing faster and larger than at any time in history. Since the 1930s, turkeys have more than doubled in size, and since the 1950s, broiler chickens have quadrupled.
To track the changes, Canadian researchers have continued raising unmodified chicken lineages and have measured them against our modern Frankensteins. Like living, breathing, chicken time capsules, these “benchmark strains” are still being bred. This allows researchers to measure commercially selected breeds, like the 2005 Ross 308 Broiler, against older genetic strains. Fed the same food, and measured at the same age, the 1957 strain weighed in at 905 grams, the 1978 strain weighed 1,808 grams, while the 2005 strain weighed 4,202 grams. The difference is enormous. Compared to birds from the 1950s, today’s modern broilers have breasts that are 80 percent larger and have increased overall in size by 400 percent.
There is a consequence to this. As we’ve deliberately grown larger animals for food, our appetites have grown as well. In 1960, the average American ate 12.7 kilograms of chicken a year, today that number has jumped to 40.8 kilograms, more than three times as much.*25 Unsurprisingly, as the beneficiaries of all this cheap meat, humans have also begun to change in size. Over the last 150 years, which is, relatively speaking, a short period, human height has increased dramatically. In industrialized countries, where is food abundant, we’ve grown taller by ten centimetres. Not only have we expanded upward though, we’ve expanded outward as well, and every country on Earth has seen its obesity rates rise.*26 In total, 2.2 billion people worldwide are classified as overweight or obese, and adults are three times more likely to be obese than they were back in 1975. Today, wild animals world over are shrinking, but human beings and our domesticated animals are ballooning in size.
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GALILEO WAS THE FIRST person on Earth to glimpse the colossal scale of reality.*27 Known today as the Father of Science, he was not only the first person to burst open the heavens with a telescope, he was also the first man to peer into a microscope and document the humble flea. It was Galileo’s good fortune to be alive at a time when glass-making was flourishing, in particular the craft of making spectacles. Then, as now, people in their forties often developed presbyopia, a condition where the lens of the eye loses flexibility with age, making it more difficult to read. In nearby Holland, the Dutch had become masters at grinding lenses to make reading glasses, and it was these spectacle makers who crafted the first rudimentary instruments that allowed us to bring into focus scales that were previously unseen.
Their intent may have been to remedy poor vision, but the spectacle makers inadvertently did much more. By boosting our vision, they revealed that humanity had been oblivious to two vast scales that secretly co-existed alongside our own. The macro and micro worlds were now made visible, and with this new and improved sight came the realization that we inhabit not only one reality, but three.
For the first time in history we could extend our human senses. And because of that, the first microscopes and telescopes were considered almost magical inventions. Spectacle-making was a secretive and competitive trade, and patent claims to these first inventions are still contested. The design of the first simple and compound microscopes is, however, generally attributed to the spectacle maker Zacharias Janssen, who began developing his new tools in 1590, and the first patent for the “spyglass,” or telescope, was filed eighteen years later, in 1608, by master lens grinder and spectacle maker Hans Lippershey.*28
Galileo was a scientist and not a spectacle maker, but once he wrapped his genius around how the scopes were made, he quickly improved upon both designs. In 1609, he created a device that he named the occhiolino, or “little eye,” a microscope that could magnify up to thirty times, ten times more than Janssen’s design. And that same year, he built his first telescope, a three-powered spyglass that rivalled Lippershey’s invention. By August 1609, he surpassed even this with a new prototype telescope, an instrument that magnified eight times, which he presented to the Venetian senate. And by October or November, he had constructed a twenty-powered telescope, and it was this one that he trained upon the skies.
Human vision may be limited, but it’s incredible when you consider what the naked eye can see even without the aid of equipment. On a clear night, a person with good eyesight can detect the flicker of a single candle flame *29 2.76 kilometres away. But, depending on the size of an object, or its brightness, we can actually see much farther away than that. The moon, for example, is 385,000 kilometres away, and our own sun is so bright that even at a distance of 150 million kilometres away it can blind us. As for the farthest single object we can see without a telescope? It is Saturn, which is 1.5 billion kilometres away. We can even see a galaxy outside of our own: Andromeda, which shines with the light of a trillion stars. There, in the distance, it flickers like a candle at 2.5 million light years, or twenty-five quintillion kilometres, away.
And all of this comes standard with our basic vision, which we test by looking at a pyramid of black letters known as the Snellen chart. Good visual acuity is the ability to accurately make out the tiny letters on the chart’s eighth row, or what we call 20/20 vision. Even in ancient times, sharp eyesight was highly valued. It goes without saying that in selecting the best warriors and hunters, it was crucial to weed out those who couldn’t spot the enemy or prey. But our ancestors had a different kind of eye test, however, one that took place not in an optician’s office but outside at night, under the canopy of stars.
The asterism called the Big Dipper hangs in the constellation of Ursa Major. It consists of seven points of starlight and forms what looks to us like a giant ladle in the sky. Zooming in to the second
star from the left on the handle, you will spot Mizar, twinkling in from seventy-eight light years away. But doubled with Mizar is a dimmer star that’s three light years behind it. We call it Alcor, but to Sufi astronomers it was known as Al-Suha, or “the forgotten one.” For the ancient Persian army—and some say, on the other side of the world, Native Americans—Alcor was nature’s Snellen chart, and the ability to distinguish between the optical double stars was the test of perfect vision.*30
With good vision so highly prized by armies, it was no surprise that Lippershey’s spyglass was an instant hit with the Dutch army. Galileo too had entrepreneurial designs for his telescope, which he pitched to the Venetians. “The power of my cannocchiale [telescope] to show distant objects as clearly as if they were near should give us an inestimable advantage in any military action on land or sea,” he assured the Doge. “At sea, we shall be able to spot their flags two hours before they can see us; and when we have established the number and type of the enemy craft, we shall be able to decide whether to pursue and engage him in battle, or take flight. Similarly, on land it should be possible from elevated positions to observe the enemy camps and their fortifications.”
In the end, it wasn’t Galileo’s ideas for military strategy but something serendipitous that occurred one evening while he was sitting outside and relaxing that forever changed how we see the universe. Instead of training his telescope on the spires of the city, Galileo arced it upward and pointed it into the sky. Through the lens, he began examining the biggest and most luminous object in the night sky, the moon. And what he saw was not at all what he expected. The moon, that perfect sphere of the heavens, was not just a smooth, glowing orb. Looking closer now he could see that it had craters. It had mountains. It had valleys and landforms that were similar to what we had on Earth. The moon, he was shocked to discover, had a landscape. And for Galileo, this was a total revelation.
Pointing his telescope up each night in “infinite amazement,” he soon began focusing on other celestial bodies. It was with his observations of Venus that our understanding of our place in the universe changed. What he noticed was that Venus had a shadow, and that, similar to the moon’s phases, it changed from a crescent back to a full, shining disc when it faced the sun. For Galileo, this could mean only one thing. Venus was not just a “wandering star”*31; it had a path. Moreover, this path was not orbiting Earth. It was orbiting the sun.
It was, in every sense of the word, a revolutionary discovery. Until that time, we had believed that the universe revolved around us. Galileo’s evidence shattered that idea and proved the Copernican theory of heliocentrism,*32 which placed the sun rather than Earth at the centre of the universe. But there would be no fanfare for Galileo’s discovery. For the Church, the observation was dangerous. In the Bible, humanity had clearly been placed at the centre of the universe by God. To believe Galileo implied that the words in the Holy Scripture were false.
So in 1616, the astronomer was summoned by the Roman Inquisition and investigated for heresy. Nicolaus Copernicus’s book On the Revolutions of the Celestial Spheres had already been banned, and it was decreed that Galileo too was to be silenced. He could no longer make any suggestion, in speech or in writing, that Earth moved around the sun. It was a remarkable moment, because, while we’ve always thought that seeing is believing, the Church was insisting that we disbelieve what we could see with our own eyes. Galileo had discovered a blind spot, but the Church wanted people to stay blind. In the short term, Galileo acquiesced, but sixteen years later he would stand trial again.
Since the days of the first telescopes, our scientific sight has sharpened tremendously, and today we can see so far into the distance we are looking back in time at the universe’s beginnings. Across the globe, hundreds of observatories dot the planet, peering into the night like big white robotic eyes. We’ve built them in cities, on mountaintops, in remote deserts, and we’ve even sent telescopes out into space. What this extraordinary level of vision means is that we only need to pick a point in the sky and then simply wait.
In September 2003, NASA astronomers did just that. They trained the Hubble Ultra Deep Field telescope on a patch next to the moon that appeared completely empty, not a star visible to the naked eye. The images it returned, however, were nothing short of mind-boggling: the “void” was clogged with ten thousand orbs of light, each orb a galaxy like our own Milky Way, home to hundreds of billions of spiralling stars. Expanding that slice of night sky, scientists have estimated that there are at least one hundred billion galaxies in our universe, filled with a sextillion stars. *33 Think of how incredible that is: we are surrounded by 1,000,000,000,000,000,000,000 stellar giants, but they are too faint for our eyes to see.*34
While we’ve been staring at the stars for millennia, it is only recently we’ve come to know that these twinkling pinpricks of light are actually massive nuclear reactors, balls of hot luminous gas that are blast furnaces of atomic fusion—that brought up close, even Alcor, barely visible as “the forgotten one,” would dwarf our own sun and, at thirteen times its brightness, burn up our entire sky. It is almost cosmic trickery, then, that from our vantage point the most massive things in the universe appear to us as if the sky were a petri dish and the stars mere specks.
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SIZE IS PHYSICAL, but it’s also a mental construct that we grapple with as well. The problem is that our brains are not very good at processing how immensely big or small things can get once they are beyond our perceptual limits. As the English writer Helen Macdonald has observed, “We are very bad at scale. The things that live in the soil are too small to care about; climate change is too large to imagine.” Instead, at imposing scales, things, objects, numbers tend to blur away into what researchers call “scale blindness.” The vastness of the universe and the infinitesimal quantum world may be fundamental to our existence, but for the most part we spend our days unaware of the larger and smaller scales we inhabit.
To illustrate what I mean, take a moment and picture in your mind a single cupcake. It should be easy. Now picture ten. Keep expanding that number up to see if you can see fifty cupcakes in your mind, or a hundred. The resolution of the cupcakes will fade, but the bulk of cupcakes should still be visible. But now, widen the scope: try to picture a thousand cupcakes, or a hundred thousand. As the number gets larger, especially to a million or a billion, our ability to envision the scale, let alone the individual cupcakes, completely breaks down. This might seem like a small issue, and it is when the topic is trivial, like cupcakes, but there are bigger implications when the topic is serious.
We may live in a world of big data, but we are numb to big numbers. And the figures that are fed to us on the news each day are mostly incomprehensible. Whether it’s the forty-six million acres of trees that are deforested each year,*35 the $20-trillion US national debt, the $1,676 billion spent annually on weapons and arms, or the twenty million people on the brink of famine and starvation, when it comes to big numbers the result is the same: our eyes glaze over and we find ourselves lost in the enormity. As Joseph Stalin is reputed to have said, “One death is a tragedy; one million is a statistic.”
As a consequence, scale blindness can be monstrous, because we can’t feel once we lose our sense of scale, and once we can’t feel, we lose the ability to react appropriately. A team of US researchers examining this sense of scale wanted to look at the effects of putting a market price on the scale of damage to life. Specifically, they wanted to know what the perceived “cost” would be of rehabilitating thousands of seabirds after an oil spill.
To see how much people were willing to pay to fix the problem, the magnitude of the hypothetical disaster was increased by a factor of ten each time. The team found that whether the number of oil-slicked birds was two thousand, twenty thousand, or two hundred thousand, the financial offer of help was about the same. Meaning scale simply did not register. On average, the subjects showed a willingness to pay about $80 to help two thous
and seabirds, but when the number of seabirds rose to twenty thousand, they offered to donate $78, or two dollars less, and when the number increased by a hundred times, to two hundred thousand birds, the price valuation rose to only $88; that’s 198,000 more birds but only an $8 difference.
If we can be so easily confused by a scale-shift of a factor of 10, imagine the blur that occurs when we re-scale by a factor of a million. Today, our microscopes are so powerful that we can magnify objects over a hundred million times, allowing us to see and move the very building blocks of the universe: atoms.*36 Physicists know, however, that even this horizon keeps shifting and that far more exists beyond the limits of what even our most advanced technologies can see. At present, what’s believed to be the farthest end of the subatomic universe—at less than 0.0000000009 yoctometres—is what’s known as the Planck length: a space that is 10-35 smaller, or thirty-five orders of magnitude smaller, than our present scale, or what we consider our daily “reality.” To put the scale of this tiny chasm in another way: a single hydrogen atom is ten trillion trillion Planck lengths across. Compared to the measure of a single Planck length, an atom is gargantuan.
Flipping over to the opposite end of the scale, the observable universe stretches out to 1026 metres, or ninety-two billion light years, away. This distance is equally unfathomable to us. To offer some perspective, one light year is just under ten trillion kilometres away. And just counting to one billion, let alone ninety-two, would take you over thirty years. “Common sense works fine for the universe we’re used to,” Carl Sagan has said, “for time scales of decades, for a space between a tenth of a millimetre and a few thousand kilometres, and for speeds much less than the speed of light. Once we leave those domains of human experience, there’s no reason to expect the laws of nature to continue to obey our expectations, since our expectations are dependent on a limited set of experiences.”
