Asteroid Threat : Defending Our Planet from Deadly Near-earth Objects (9781616149147) Read online

  Inevitably, one entrepreneur offered what he called an “Apocalypse tour” around Lake Chebarkul that ended where large chunks of the meteorite were believed to have crashed through the ice, leaving a large hole. Divers searched the bottom of the lake under the hole and found nothing. Andrei Orlov, the mayor of Chebarkul, reportedly wrote on his blog that he had been told that the town of forty thousand “really got lucky.” Six days after the remnants of the meteorite plunged into the lake, he called for a citywide brainstorming session on the best way to get the news into travel brochures and books that would attract foreigners and other Russians to the site where the heavens sent an emissary. He and the other town fathers even thought about opening an American-style “Meteor Disneyland”—a theme park that would attract tourists with exhibitions and rides that taught about the dangers lurking in the sky. (They ended the dinosaurs, after all.) The theme park would also celebrate the town for having been the target of an actual impactor and having survived a near miss.33

  The entrepreneurs were not only in Chelyabinsk and its environs. Some were in America, which abounds in entrepreneurs. An Internet retailer called Zazzle in Redwood City, California, quickly advertised a line of T-shirts that said, “Meteorite Survivor Feb. 15, 2013” and “I Survived the Russian Meteor,” available in eighteen colors for $19.40 (plus shipping). There was also an “I Love Meteorites” T-shirt with the usual red heart in place of the word Love, a mug with “I eat, sleep and breathe meteorites 24/7” that went for $14.95, a sky rock travel mug at $22.95, an Armageddon poster that cost $21.35, and, perhaps inevitably, a poster that was priced at $12.75 and a sticker that cost $4.95, both of which said, “Kiss My Asteroid.” Someone even concocted a Kiss My Asteroid cocktail, with liqueurs and pineapple juice over crushed ice, to sip while giving “that meteor the finger.”34

  As will be seen, catastrophes can be profitable as well as painful.

  That Chelyabinsk had been spared a calamity was immediately obvious to its inhabitants, others in the region, all Russians, and foreigners who knew about the incident. But something else good came of it that was not immediately obvious. A common, existential threat brought cooperation and mutual empathy to a troubled industrial community that had long suffered from miserable weather, hard working conditions in factories, and the Mayak and other accidents that resulted in the suffering—or death—of many and made Chelyabinsk the most contaminated place in the world. But the threat that came from space and that did not make distinctions among its victims bonded them into a cohesive and mutually supportive community. They would have remembered that when the danger passed. Common danger from beyond this world can and should compel people everywhere to maintain mutual protection and a common defense of the planet.

  It's hard to love an asteroid. Once upon a time, there was a little prince who lived on one that he thought was a star. It was called B612, and it was hardly bigger than he was. “When you look up at the sky at night,” he told Antoine de Saint-Exupéry, the French aviator and writer, “since I'll be living on one of them, for you it'll be as if all the stars are laughing. You'll have stars that can laugh!”1

  Stars may laugh. But with the exception of B612, asteroids are no laughing matter, and neither are their icy cousins, the comets. Every solid body in this Solar System bears scars from collisions with one or the other (or both). Except for His Highness, asteroids in particular have few if any friends, since astronomers and other scientists know that they are exactly what they appear to be: rocks, often laced with iron, moving at such high velocities that they can inflict horrendous damage when they strike.

  Comets, which have been imbued with magical beauty in the popular imagination since ancient times—they're the shimmering celebrities of the night sky that have long, curvaceous tails and have, from time immemorial, been taken to be the emissaries of the gods and therefore precede momentous events—are the asteroids’ icy counterparts. They, too, carry the potential for death and destruction, but their appearance is deceptive. Asteroids are the obvious, potentially deadly villains of the universe and are generally thought to be an unmitigated menace. But comets have been adored, celebrated, and feared as omens throughout recorded history and undoubtedly long before then.

  “Comets, of course, are obvious candidates for the lead in any drama of outer space, because of their spectacular appearance,” Robert Shapiro, a retired professor of chemistry at New York University and an authority on the origin of life, has written. “These objects, with their shining heads and long tails, have turned up in the night sky at various times in human history and inevitably made a profound impression. The sight of a comet was taken as a signal that a very important event was about to occur.” He quotes Calpurnia in Shakespeare's Julius Caesar on the subject: “When beggars die there are no comets seen; The heavens themselves blaze forth the death of princes.”2

  The blazing, long-tailed “messengers” have been credited with carrying complex organic molecules around the universe and, by implication, with bringing life to this planet and very possibly to others as well. Sir Fred Hoyle and Nalin C. Wickramasinghe made that point in Lifecloud: The Origin of Life in the Universe, which was published in 1978 and helped to popularize the modern debate on where life as we know it originated. They hypothesized that too many diverse elements of nature would've had to have acted in symphony in a relatively short period of time on this planet for life to have developed spontaneously. “The best explanation therefore of the known facts relating to the origin of life on Earth is that in the early days soft landings of comets brought about the spreading of water and other volatiles over the Earth's surface. Then about four billion years ago life also arrived from a comet that delivered it here. By that time conditions on the Earth had become sufficiently similar to those on the cometary home for life to be able to persist here, probably at first tentatively and then with some assurance as time went on. The long evolution of life on the earth had begun.”3

  Hoyle and Wickramasinghe were so fascinated by comets, and particularly by their potential for being cosmic-life transportation systems, that Lifecloud was followed by Diseases from Space. Therein, they claimed that comets were also responsible for delivering the viruses and bacteria that inflict infectious diseases on animals and plants on this planet. The first chapter contains the nut graf, as they call it in journalism (or the point of the story):

  We shall be presenting arguments and facts which support the idea that the viruses and bacteria responsible for the infectious diseases of plants and animals arrive at the Earth from space. Furthermore, we shall argue that apart from their harmful effect, these same viruses and bacteria have been responsible in the past for the origin and evolution of life on Earth. In our view, all aspects of the basic biochemistry of life come from outside the Earth.4

  In the eternal cast of characters in the universe, then, that makes comets both Dr. Jekyll and Mr. Hyde.

  Geologist Gene Shoemaker, who invented planetary geology and became the de facto first planetary scientist, may also have thought that stars are a laughing matter. But he certainly knew better than to believe the same about asteroids and comets. He once explained the asteroid threat as he walked around the rim of Meteor Crater near Flagstaff, Arizona, thus putting it in the kind of perspective that is the mark of a great teacher. The crater itself was caused by an impact that was roughly 150 times the force of the atomic bombs that virtually obliterated Hiroshima and killed an estimated sixty-six thousand of its inhabitants. The asteroid or comet that made Meteor Crater would have turned the hearts—or epicenters, as the natural-disaster crowd calls them—of New York, Paris, Moscow, Beijing, Cairo, Nairobi, Melbourne, or any other metropolis packed with people into a vast, smoking ditch filled with grotesquely twisted and smoking rubble and the mangled, bloody remains of millions of people and animals. It has been estimated that a 140-meter-wide rock or chunk of ice—that's about one and a half times the size of the proverbial football field—moving at high velocity could inflict that level of de
struction. Shoemaker therefore took the impact hazard out of the realm of the esoteric, which is the way most scientists think about it, and put it where it belongs.

  “One thing that makes the comet and asteroid impact hazard so important relative to other hazards is that it is the one hazard that is capable of killing billions of people; of putting at risk our entire civilization,” Shoemaker continued. “We can have any number of storms or earthquakes or volcanoes, and they can do terrible damage locally, but they do not put the entire planet at risk the way an impact does.” Put another way, the relative difference in destructive capacity between homegrown disasters such Hurricane Katrina—which struck New Orleans and elsewhere at the end of August 2005, killing almost two thousand people and causing almost $82 billion in property damage—or the earthquake that devastated Porto Prince, Haiti, almost five years after Katrina, and a collision with a large asteroid or comet is the difference between the explosion of a conventional bomb and a thermonuclear one.

  “It's like being in a hail of bullets going by all the time,” Shoemaker added. “They are bullets. They're bullets out there in space.” For years, Gene Shoemaker and a few of his predecessors and colleagues waged an intellectual war with many other scientists who were just as firmly convinced that craters here on this planet, as well as those on the Moon, Mercury, and elsewhere were caused by erupting volcanoes, not asteroids, comets, and other solid objects that fly around space in all directions at terrific speed. And as creation “scientists” argue that life came to Earth in a highly structured form (though not necessarily on a comet), contrary to what Darwin and the evolutionists who followed him demonstrated, those who believed that all the craters on every planet with a surface and their moons were caused only by volcanoes stubbornly stuck to their theory, evidence to the contrary notwithstanding.5

  But the evidence of impacts is overwhelming, and the threat is real. Gene Shoemaker's “bullets” are actually tearing around this Solar System by the many thousands, and possibly millions, all the time (though relatively few are potential city-killers, let alone planet-killers). Given the number of planets and moons, collisions with the speeding rocks around them are therefore inevitable. Mercury has so many impact craters that it looks as though it has been bombarded by artillery fire since it came into existence. And that, in effect, is exactly what happened.

  Asteroid- and comet-impact craters are almost all over this world. Estimates of the number of large ones varies considerably because, unlike the Moon, Mercury, Mars, and other planets and moons with surfaces, Earth is a living entity and is therefore subject to the growth of vegetation that can cover or disguise craters, deserts and oceans that can hide them, and wind erosion that can practically erase them altogether. Furthermore, establishing size is subjective. The estimated number of large craters—and the definition of size is somewhat subjective—therefore varies from 139 to more than 170. There is overwhelming agreement, however, that the largest crater on the planet that has been discovered so far is the Vredefort crater in South Africa, which is three hundred kilometers wide and was made about two billion years ago. It makes Meteor Crater look like a pothole in comparison.6

  But it was the impact at what is now Mexico's Yucatan Peninsula, centered at a spot called Chicxulub, that the overwhelming number of experts are convinced finished off the dinosaurs and many other creatures roughly sixty-five million years ago. The explosion played such a decisive role in Earth's history that scientists use it as a dividing event to separate the planet's two distinct geological periods: the Cretaceous and the Tertiary, commonly known as the K-T boundary. That horrendous impact did a great deal more than make the dinosaurs and some other species of animals and vegetation disappear. It profoundly affected the structure of the planet itself by abruptly changing its geology, topography, and climate. But it was by no means the worst hit Earth has taken. The record was established about four and a half billion years ago, when something the size of a small planet crashed into this one with such force that it broke off a huge chunk of the Earth, which went into orbit around itself and became its solitary moon. As is the case with so much of Earth's formative period, how the Moon came to be has also been the subject of widely varying theories.

  Like all good scientists, Shoemaker was part Sherlock Holmes, so he searched for and found clues relating to Earth's early history and that of its lone natural satellite. As the great sleuth himself would have said, the clues are often hidden in plain sight and are obvious to the trained eye and open mind. This process can be seen in the dialogue between Sherlock Holmes and Dr. Watson, taken from the 1943 film Sherlock Holmes and the Secret Weapon (loosely based on the Sir Arthur Conan Doyle short story “The Adventure of the Dancing Men”). The film is about a scientist who invented a top-secret bombsight and, in order to take the invention for himself, was abducted by Holmes's consummately evil nemesis, Professor James Moriarty. Holmes and Watson attempt to decode a message from the scientist:

  “I'm all in. Can't think anymore,” Dr. Watson complained to Holmes after seeing a message written in a jumbled stick figure code by the scientist. “All these letters and figures running through my brain; all twisted round.”

  “Twisted round!” Holmes exclaimed.

  “That's it. ‘Twisted round,’ you said. So simple I never thought of it. Reverse the slide. You see that one? It's now identical with the first three names. In other words, all the figures that have number four are written backwards so it reads from right to left, until we reverse the slide, when they read correctly from left to right.”

  (Elementary, my dear Watson.) Watson was duly awed yet again by his friend and roommate at 221B Baker Street.

  That deductive process was used with an equally positive result when Shoemaker and his wife, Carolyn, happened on the town of Nordling while they were on vacation in southern West Germany in 1961. Their adventure was later made into a National Geographic special called Asteroids: Deadly Impact, which was filmed for public broadcasting.

  Nordling was built in the center of a very large, somewhat-shallow bowl called the Ries Basin. It was there that Shoemaker had his Holmes-like revelation. Looking down at the bowl from its rim, just as he had at Meteor Crater and other large depressions, Shoemaker became convinced that it had in fact been caused by a kilometer-sized or larger rock that struck the site and exploded on impact roughly fifteen million years ago.

  Like most such pervasively tidy, red-roofed towns in the region, Nordling has a cathedral named St. George's. And, like the town itself, St. George's dates back to medieval times. The Shoemakers drove into Nordling in an orange-and-blue Volkswagen camper minibus that spring day, parked it, and walked through the town square and up to the front of St. George's. They stopped at the left side of the main entrance. Then he began to look intently at one of the thousands of large stones that had been laboriously chiseled into the shape of rough cubes and cemented in place to make the edifice's walls. The grayish stones caught Shoemaker's eye because tiny parts of them glittered. While scrutinizing one of the stone cubes very closely, he spotted tiny pieces of shimmering silica—primitive glass—embedded in it. He knew that glass is made under high pressure and in extreme heat. Asteroids and comets that slam into the atmosphere do so under immense pressure and become very hot. That's why they glow as they race across the night sky. And the deeper they penetrate into the thickening atmosphere, the hotter they get, so they are hottest at the instant of impact. The rock that made the crater in which Nordling was built, Shoemaker deduced as Holmes would have, was moving so fast and was so hot when it struck that it turned fragments of the rocks it struck into silica. The crater and the silica in its stones that were used to make the cathedral told a very vivid and logical story to Shoemaker. “It was the first impact crater which we could prove was an impact crater,” he later recalled in triumph. “That just changed the whole ballgame.”7 (Elementary, my dear Carolyn.)

  And, Gene Shoemaker added, the next time a really big asteroid or comet strikes the ho
me planet, “It will produce a catastrophe that exceeds all the other catastrophes by a large measure. These things have hit the Earth in the past. They will hit Earth in the future,” he added, matter-of-factly. A rock that is more than a kilometer in diameter would create an explosion on impact equivalent to all the world's nuclear weapons going off at the same instant, he said. “Actually,” he corrected, “it would be a little bit more energy than that.” The eruption of Earth and everything on it would fill the sky with so much debris that it would darken the world for months. It would cause “mass hysteria,” Carolyn added.8

  David H. Levy, a prolific and ubiquitous Canadian with widely varying interests who claims to be “one of the most successful comet discoverers in history” (he spotted eight of them using telescopes in his backyard, according to his resume) is a longtime friend of the Shoemakers who appeared with them on that National Geographic special. He drew a vivid analogy in describing how a human would feel if he or she were near an impact explosion like the one that caused the crater in which Nordling was built. “You would feel as though you were in an oven turned to broil,” he said.9

  The most momentous time in Levy's and the Shoemakers’ lives began on March 25, 1993, when Carolyn spotted what looked like a “squashed comet” in a photograph of the space around Jupiter they had taken as part of their routine photos two days earlier at the Mount Palomar Observatory in California. They were perplexed because, instead of a nucleus trailing a long tail, which is what comets are supposed to look like, this one was bar shaped and seemed to have a series of little tails. Close analysis of the picture under a microscope showed that the “bar” was in fact a string of twenty or twenty-one cometary fragments—a formation of them—bearing down on the giant planet in what was a near-certain collision course. They quickly alerted the astronomical community, and from July 16 to 22, 1994, the three of them and the rest of the world were treated to the first look humans have ever had of a collision between a planet and its cosmic attackers. They watched, almost in disbelief, as the huge chunks of ice successively plowed into Jupiter at a velocity they estimated to be sixty kilometers a second. The largest of the impactors was calculated to be two kilometers in diameter. Each strike left intensely hot gas bubbles and large, dark scars in Jupiter's atmosphere that remained for months. Plumes of gas thousands of kilometers high shot into the atmosphere. It was the first—and so far the only—time when humans have actually gotten to witness an attack on a planet. Levy has written about it, starting with the first of the historic impacts: