Space Chronicles: Facing the Ultimate Frontier (16 page)

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Authors: Neil deGrasse Tyson,Avis Lang

BOOK: Space Chronicles: Facing the Ultimate Frontier
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And the onward momentum toward insignificance continued with a vengeance.

In the 1920s and 1930s, physicists demonstrated that the fuel source in the Sun was the thermonuclear fusion of hydrogen into helium. In the 1940s and 1950s astrophysicists deduced the cosmic abundance of elements by describing in detail the sequence of thermonuclear fusion that unfolds in the cores of high-mass stars that explode at the end of their lives, enriching the universe with elements from all over the famed periodic table, the top five being hydrogen, helium, oxygen, carbon, and nitrogen. That very same sequence (except for helium, which is chemically inert) pops up when we look at the chemical constituents of human life. So, not only is our existence as human beings not special; neither are the ingredients of life itself.

So there you have it: the capsule summary of how cosmic discovery began by glorifying God, descended into glorifying human life, and ended up by insulting our collective human ego.

The Future of Discovery

 

When (or if) space ever becomes our final frontier, it will represent uncharted territories akin to those the ancient explorers dreamed of conquering. The coming voyages to space may be economically driven, for example by the intent to mine million-ton asteroids for their mineral resources. Or perhaps the voyages will be motivated by survival, spurred by the intent to spread the human species around the galaxy as much as possible so as to avoid total human extinction from a catastrophic, once-in-a-hundred-million-year collision with a comet or asteroid.

The golden era of space exploration was no doubt the 1960s. At that time, though, the significance of the space program was somewhat muddled in many urban centers because of widespread poverty, crime, and problem-ridden schools. Five decades later, the significance of the space program remains muddled in many urban centers because of widespread poverty, crime, and problem-ridden schools. But there’s a fundamental difference. In the 1960s, discoveries in space were something that people looked forward to. Today many people—including me—are looking back at them.

I remember the day, and the moment, when the Apollo 11 astronauts stepped foot on the Moon. That landing, on July 20, 1969, was of course one of the twentieth century’s greatest moments. Yet I found myself somewhat indifferent to the event—not because I couldn’t appreciate its rightful place in human history, but because I had every reason to believe that trips to the Moon would soon take place monthly. Frequent Moon voyages were simply the next step; little did I know there would be a flurry of them in the twentieth century, followed by nothing for decades.

Yes, the funding stream for the space program had been primarily defense-driven. Cosmic dreams, and the innate human desire to explore the unknown, were of lesser import. But the word “defense” can be reinterpreted to mean something far more important than armies and arsenals. It can mean the defense of the human species itself. In July 1994 the equivalent of more than 200,000 megatons of TNT was deposited in Jupiter’s upper atmosphere as comet Shoemaker-Levy 9 slammed into the planet. If that kind of collision happens on Earth while humanity is present, it would very likely result in the abrupt extinction of our species.

Defense of our existence mandates a very real agenda. To achieve it, we must acquire maximal understanding of Earth’s climate and ecosystem, so as to minimize the risk of self-destruction, and we must colonize space in as many places as possible, thereby proportionally reducing the chance of species annihilation owing to a collision between Earth and an asteroid or comet discovered by an amateur astronomer.

The fossil record teems with extinct species. Many of them, before disappearing, thrived far longer than the current Earth tenure of
Homo sapiens
. Dinosaurs are extinct today because they did not build spacecraft. Were no funds available? Did their politicians lack foresight? More likely it was because their brains were tiny. And the absence of an opposable thumb didn’t help either.

For humans to become extinct would be the greatest tragedy in the history of life in the universe—because the reason for it would be not that we lacked the intelligence to build interplanetary spacecraft, or that we lacked an active program of space travel, but that the human species itself turned its back and chose not to fund such a survival plan. Make no mistake: the path to discovery inherent in space exploration has become not a choice but a necessity, and the consequences of that choice affect the survival of absolutely everyone, including those who remain thoroughly unenlightened by the multitude of discoveries made by their own species throughout its time on Earth.

• • •
CHAPTER THIRTEEN

 

TO FLY
*

 

In ancient days two aviators procured to themselves wings. Daedalus flew safely through the middle air, and was duly honoured in his landing. Icarus soared upwards to the sun till the wax melted which bound his wings, and his flight ended in a fiasco. In weighing their achievements perhaps there is something to be said for Icarus. The classic authorities tell us, of course, that he was only “doing a stunt”; but I prefer to think of him as the man who certainly brought to light a serious constructional defect in the flying-machines of his day [and] we may at least hope to learn from his journey some hints to build a better machine.

 


S
IR
A
RTHUR
E
DDINGTON,
Stars & Atoms
(1927)

 

For millennia, the idea of being able to fly occupied human dreams and fantasies. Waddling around on Earth’s surface as majestic birds flew overhead, perhaps we developed a form of wing envy. One might even call it wing worship.

You needn’t look far for evidence. For most of the history of broadcast television in America, when a station signed off for the night, it didn’t show somebody walking erect and bidding farewell; instead it would play the “Star Spangled Banner” and show things that fly, such as birds soaring or Air Force jets whooshing by. The United States even adopted a flying predator as a symbol of its strength: the bald eagle, which appears on the back of the dollar bill, the quarter, the Kennedy half dollar, the Eisenhower dollar, and the Susan B. Anthony dollar. There’s also one on the floor of the Oval Office in the White House. Our most famous superhero, Superman, can fly upon donning blue pantyhose and a red cape. When you die, if you qualify, you might just become an angel—and everybody knows that angels (at least the ones who have earned their wings) can fly. Then there’s the winged horse Pegasus; the wing-footed Mercury; the aerodynamically unlikely Cupid; and Peter Pan and his fairy sidekick, Tinkerbell.

Our inability to fly often goes unmentioned in textbook comparisons of human features with those of other species in the animal kingdom. Yet we are quick to use the word “flightless” as a synonym for “hapless” when describing such birds as the dodo and the booby, which tend to find themselves on the wrong end of evolutionary jokes. We did, however, ultimately learn to fly because of the technological ingenuity afforded by our human brains. And of course, while birds can fly, they are nonetheless stuck with bird brains. But this self-aggrandizing line of reasoning is somewhat flawed, because it ignores all the millennia that we were technologically flightless.

I
remember as a student in junior high school reading that the famed physicist Lord Kelvin, at the turn of the twentieth century, had argued the impossibility of self-propelled flight by any device that was heavier than air. Clearly this was a myopic prediction. But one needn’t have waited for the invention of the first airplanes to refute the essay’s premise. One merely needed to look at birds, which have no trouble flying and, last I checked, are all heavier than air.

Space Tweet #14

USAirForce has styled bird wings as symbol. But we now fly at speeds that’d vaporize a bird, & in space, wings are useless

Sept 30, 2010 1:01
PM

 

If something is not forbidden by the laws of physics, then it is, in principle, possible, regardless of the limits of one’s technological foresight. The speed of sound in air ranges from seven hundred to eight hundred miles per hour, depending on the atmospheric temperature. No law of physics prevents objects from going faster than Mach 1, the speed of sound. But before the sound “barrier” was broken in 1947 by Charles E. “Chuck” Yeager, piloting the Bell X-1 (a US Army rocket plane), much claptrap was written about the impossibility of objects moving faster than the speed of sound. Meanwhile, bullets fired by high-powered rifles had been breaking the sound barrier for more than a century. And the crack of a whip or the sound of a wet towel snapping at somebody’s buttocks in the locker room is a mini sonic boom, created by the end of the whip or the tip of the towel moving through the air faster than the speed of sound. Any limits to breaking the sound barrier were purely psychological and technological.

During its lifetime, the fastest winged aircraft by far was the space shuttle, which, with the aid of detachable rockets and fuel tanks, exceeded Mach 20 on its way to orbit. Propulsionless on return, it fell back out of orbit, gliding safely down to Earth. Although other craft routinely travel many times faster than the speed of sound, none can travel faster than the speed of light. I speak not from a naiveté about technology’s future but from a platform built upon the laws of physics, which apply on Earth as they do in the heavens. Credit the Apollo astronauts who went to the Moon with attaining the highest speeds at which humans have ever flown: about seven miles per second at the end of the rocket burn that lifted their craft beyond low Earth orbit. This is a paltry 1/250 of one percent of the speed of light. Actually, the real problem is not the moat that separates these two speeds but the laws of physics that prevent any object from ever achieving the speed of light, no matter how inventive your technology. The sound barrier and the light barrier are not equivalent limits on invention.

The Wright brothers of Ohio are, of course, generally credited with being “first in flight” at Kitty Hawk, North Carolina, as that state’s license-plate slogan reminds us. But this claim needs to be further delineated. Wilbur and Orville Wright were the first to fly a heavier-than-air, engine-powered vehicle that carried a human being—Orville, in this case—and that did not land at a lower elevation than its takeoff point. Previously, people had flown in balloon gondolas and in gliders and had executed controlled descents from the sides of cliffs, but none of those efforts would have made a bird jealous. Nor would Wilbur and Orville’s first trip have turned any bird heads. The first of their four flights—at 10:35
A.M.
eastern time on December 17, 1903—lasted twelve seconds, at an average speed of 6.8 miles per hour against a 30-mile-per-hour wind. The
Wright Flyer
, as it was called, had traveled 120 feet, not even the length of one wing on a Boeing 747.

E
ven after the Wright brothers went public with their achievement, the media took only intermittent notice of it and other aviation firsts. As late as 1933—six years after Lindbergh’s historic solo flight across the Atlantic—H. Gordon Garbedian ignored airplanes in the otherwise prescient introduction to his book
Major Mysteries of Science:

 

Present day life is dominated by science as never before. You pick up a telephone and within a few minutes you are talking with a friend in Paris. You can travel under sea in a submarine, or circumnavigate the globe by air in a Zeppelin. The radio carries your voice to all parts of the earth with the speed of light. Soon, television will enable you to see the world’s greatest spectacles as you sit in the comfort of your living room.

 

But some journalists did pay attention to the way flight might change civilization. After the Frenchman Louis Blériot crossed the English Channel from Calais to Dover on July 25, 1909, an article on page three of the
New York Times
was headlined “F
RENCHMAN
P
ROVES
A
EROPLANE
N
O
T
OY
.” The article went on to delineate England’s reaction to the event:

 

Editorials in the London newspapers buzzed about the new world where Great Britain’s insular strength is no longer unchallenged; that the aeroplane is not a toy but a possible instrument of warfare, which must be taken into account by soldiers and statesmen, and that it was the one thing needed to wake up the English people to the importance of the science of aviation.

 

The guy was right. Thirty-five years later, not only had airplanes been used as fighters and bombers in warfare but the Germans had taken the concept a notch further and invented the V-2 to attack London. Their vehicle was significant in many ways. First, it was not an airplane; it was an unprecedentedly large missile. Second, because the V-2 could be launched several hundred miles from its target, it basically birthed the modern rocket. And third, for its entire airborne journey after launch, the V-2 moved under the influence of gravity alone; in other words, it was a suborbital ballistic missile, the fastest way to deliver a bomb from one location on Earth to another. Subsequently, Cold War “advances” in the design of missiles enabled military power to target cities on opposite sides of the world. Maximum flight time? About forty-five minutes—not nearly enough time to evacuate a targeted city.

While we can say they’re suborbital, do we have the right to declare missiles to be flying? Are falling objects in flight? Is Earth “flying” in orbit around the Sun? In keeping with the rules applied to the Wright brothers, a person must be onboard the craft and it must move under its own power. But there’s no rule that says we cannot change the rules.

K
nowing that the V-2 brought orbital technology within reach, some people got impatient. Among them were the editors of the popular, family-oriented magazine
Collier’s
, which sent two journalists to join the engineers, scientists, and visionaries gathered at New York City’s Hayden Planetarium on Columbus Day, 1951, for its seminal Space Travel Symposium. In the March 22, 1952, issue of
Collier’s
, in a piece titled “What Are We Waiting For?” the magazine endorsed the need for and value of a space station that would serve as a watchful eye over a divided world:

 

In the hands of the West a space station, permanently established beyond the atmosphere, would be the greatest hope for peace the world has ever known. No nation could undertake preparations for war without the certain knowledge that it was being observed by the ever-watching eyes aboard the “sentinel in space.” It would be the end of the Iron Curtains wherever they might be.

 

We Americans didn’t build a space station; instead we went to the Moon. With this effort, our wing worship continued. Never mind that Apollo astronauts landed on the airless Moon, where wings are completely useless, in a lunar module named after a bird. A mere sixty-five years, seven months, three days, five hours, and forty-three minutes after Orville left the ground, Neil Armstrong gave his first statement from the Moon’s surface: “Houston, Tranquillity Base here. The Eagle has landed.”

The human record for “altitude” does not go to anybody for having walked on the Moon. It goes to the astronauts of the ill-fated Apollo 13. Knowing they could not land on the Moon after the explosion in their oxygen tank, and knowing they did not have enough fuel to stop, slow down, and head back, they executed a single figure-eight ballistic trajectory around the Moon, swinging them back toward Earth. The Moon just happened to be near apogee, the farthest point from Earth in its elliptical orbit. No other Apollo mission (before or since) went to the Moon during apogee, which granted the Apollo 13 astronauts the human altitude record. (After calculating that they must have reached about 245,000 miles “above” Earth’s surface, including the orbital distance from the Moon’s surface, I asked Apollo 13 commander Jim Lovell, “Who was on the far side of the command module as it rounded the Moon? That single person would hold the altitude record.” He refused to tell.)

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