Carl Sagan’s “Pale Blue Dot”: Still Timely Excerpts

We all know the famous goosebump-raising, tear-eliciting passage beginning “Look again at that dot…” But there’s much more here to savor. While much of Pale Blue Dot is devoted to summarizing the state of planetary exploration as of 1997, when the book was published, there remain many fascinating observations that are still relevant. I’ve tried to digest these here.


spinning blue dot[11]

A rather poetic summary of space exploration so far

Since the advent of successful interplanetary flight in 1962, our machines have flown by, orbited, or landed on more than seventy new worlds. We have wandered among the wanderers. We have found vast volcanic eminences that dwarf the highest mountain on Earth; ancient river valleys on two planets enigmatically one too cold and the other too hot for running water; a giant planet with an interior of liquid metallic hydrogen into which a thousand Earths would fit; whole moons that have melted; a cloud-covered place with an atmosphere of corrosive raids, where even the high plateaus are above the melting point of lead ancient surfaces on which a faithful record of the violent formation of the Solar System is engraved; refugee ice worlds from the transplutonian depths; exquisitely patterned ring systems, marking the subtle harmonies of gravity; and a world surrounded by clouds of complex organic molecules like those that in the earliest history of our planet led to the origin of life.

[p 7-8]

spinning blue dot[13]

Ah yes, the famous bit, from the chapter “You Are Here”

The spacecraft was a long way from home,

beyond the orbit of the outermost planet and high above the ecliptic plane… The ship was speeding away from the Sun at 40,000 miles per hour. But in early February of 1990, it was overtaken by an urgent message from Earth… Voyager 1 was so high above the ecliptic plane because, in 1981, it had made a close pass by Titan, the giant moon of Saturn. Its sister ship, Voyager 2, was dispatched on a different trajectory, within the ecliptic plane, and so she was able to perform her celebrated explorations of Uranus and Neptune. The two Voyager robots have explored four planets and nearly sixty moons… I thought it might be a good idea, just after Saturn, to have them take one last glance homeward…

Look again at that dot. That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, ever king and peasant, every young couple in love, every moth and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every “superstar,” every “supreme leader,” every saint and sinner in the history of our species lived there—on a mote of dust suspended in a sunbeam.

The Earth is a very small stage in a vast cosmic arena. Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become momentary masters of a fraction of a dot. Think of the endless visited by the inhabitants of one corner of this pixel the scarcely distinguishable inhabitants of some other corner, how frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds.

Our posturings, our imagined self-importance, the delusion that we have some privileged position in the Universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves.

The Earth is the only world known so far to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment the Earth is where we make our stand.

It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we’ve ever known.

[p 12-13]

spinning blue dot[16]

On the arrogance of religions that claim the universe was made for us

It almost never feels like prejudice. Instead, it seems fitting and just—the idea that, because of an accident of birth, our group (whichever one it is) should have a central position in the social universe. Among Pharaonic princelings and Plantagenet pretenders, children of robber barons and Central Committee bureaucrats, street gangs and conquerors of nations, members of confident majorities, obscure sects, and reviled minorities, this self-serving attitude seems as natural as breathing. It draws sustenance from the same psychic wellsprings as sexism, racism, nationalism, and the other deadly chauvinisms that plague our species. Uncommon strength of character is needed to resist the blandishments of those who assure us that we have an obvious, even God-given, superiority over our fellows…

Indeed, many of the central debates in the history of science seem to be, in part at least, contests over whether humans are special… The entire Universe, made for us! We must really be something…

We seem to crave privilege, merited not by our work, but by our birth, by the mere fact that, say, we are humans and born on Earth. We might call it the anthropocentric—the “human-centered”—conceit.

This conceit is brought close to culmination in the notion that we are created in God’s image: The Creator and Ruler of the entire Universe looks just like me. My, what a coincidence. How convenient and satisfying!

Modern science has been a voyage into the unknown, with a lesson in humility waiting at every stop.

Perhaps the clearest indication that the search for an unmerited privileged position for humans will never be wholly abandoned is what in physics and astronomy is called the Anthropic Principle. It would be better named the Anthropocentric Principle….[S]ome of their advocates come close to deducing that the laws of Nature and the values of the physical constants were established (don’t ask how or by Whom) so that humans would eventually come to be…

It sounds like playing my first hand of bridge, winning, knowing that there are 54 billion billion billion (5.4 X 1028) possible other hands that I was equally likely to have been dealt, and then foolishly concluding that a god of bridge exists and favors me, a god who arranged the cards and the shuffle with my victory foreordained from The Beginning. We do not know how many other winning hands there are in the cosmic deck, how many other kinds of universes, laws of Nature, and physical constants: that could also lead to life and Intelligence and perhaps even delusions of self-importance…

Which laws of Nature go with which others? Are there meta-laws specifying the connections? Can we possibly discover them? Of all conceivable laws of gravity, say, which ones can exist simultaneously with which conceivable laws of quantum physics that determine the very existence of macroscopic matter? Are all laws we can think of possible, or is there only a restricted number that can somehow be brought into existence? Clearly we have not a glimmering of how to determine which laws of Nature are “possible” and which are not…

For example, Newton’s universal law of gravitation specifies that the mutual gravitational force attracting two bodies towards each other is inversely proportional to the square of how far they are apart… But if this exponent were different—if the gravitational law were 1/r4, say, rather than 1/r2 —then the orbits would not close; over billions of revolutions, the planets would spiral in and be consumed in the fiery depths of the Sun, or spiral out and be lost to interstellar space. If the Universe were constructed with an inverse fourth power law rather than an inverse square law, soon there would be no planets for living beings to inhabit.

So of all the possible gravitational force laws, why are we so lucky as to live in a universe sporting a law consistent with life? First of course, we’re so “lucky,” because if we weren’t, we wouldn’t be here to ask the question. It is no mystery that inquisitive beings who evolve on planets can be found only in universes that admit planets. Second, the inverse square law is not is the only one consistent with stability over billions of years. Any power law less steep than 1/r3 (1/r2.99 or 1/r, for example) will keep a planet in the vicinity of a circular orbit even if it’s given a shove. We have a tendency to overlook the possibility that other conceivable laws of Nature might also be consistent with life.

But there’s a further point: It’s not arbitrary that we have an inverse square law of gravitation. When Newton’s theory is understood in terms of the more encompassing general theory of relativity, we recognize that the exponent of the gravity law is 2 because the number of physical dimensions we live in is 3. All gravity laws aren’t available, free for a Creator’s choosing. Even given an infinite number of three-dimensional universes for some great god to tinker with, the gravity law would always lave to be the law of the inverse square… the ideas of gravity and mass are not separate matters, but ramifications of the underlying geometry of space-time.

I wonder if something like this doesn’t apply generally to all anthropic hypotheses. The laws or physical constants on which our lives depend turn out to be members of a class, perhaps even a vast class, of other laws and other physical constants—but some of these are also compatible with a kind of life…

There is something stunningly narrow about how the Anthropic Principle is phrased. Yes, only certain laws and constants of nature are consistent with our kind of life. But essentially the same laws and constants are required to make a rock. So why not talk about a Universe designed so rocks could one day come to be, and strong and weak Lithic Principles? If stones could philosophize, I imagine Lithic Principles would be at the intellectual frontiers.

There are cosmological models being formulated today… [of] a vast Cosmos, much larger than our Universe… We imagine our universe to be unique, but it is one of an immense number—perhaps an infinite number—of equally valid, equally independent, equally isolated universes. There will be life in some, and not in others. In this view the observable Universe is just a newly formed backwater of a much vaster, infinitely old, and wholly unobservable Cosmos…

Strong Anthropic Principle ideas are not amenable to proof… if self-congratulatory pretensions to centrality have now retreated to such bastions impervious to experiment, then the sequence of scientific battles with human chauvinism would seem to have been, at least largely, won…

We have not been given the lead in the cosmic drama.

Perhaps someone else has. Perhaps no one else has. In either case, we have good reason for humility.

[p 15-19, 25-28]

spinning blue dot[20]

On creationism

The universe is said to be exactly as old as the Earth. This is still the standard of Jewish, Christian, and Moslem fundamentalists and is clearly reflected in the Jewish calendar… But so young a Universe raises an awkward question: How is it that there are astronomical objects more than 6,000 light-years away? It takes light a year to travel a light-year, 10,000 years to travel 10,000 light-years, and so on… If… we were to accept the literal truth of such religious books, how could we reconcile the data? The only plausible conclusion, I think, is that God recently made all the photons of light arriving on the Earth in such a coherent format as to mislead generations of astronomers into the misapprehension that there are such things as galaxies and quasars, and intentionally driving them to the spurious conclusion that the Universe is vast and old. This is such a malevolent theology I still have difficulty believing that anyone, no matter how devoted to the divine inspiration of any religious book, could seriously entertain it.

[p 21]

spinning blue dot[25]

On the Catholic Church now pretending it just LOVED Galileo

[The Church] still cannot quite bring itself, though, to see the significance of its opposition [to Galileo]. In a 1992 speech Pope John Paul II argued,

‘From the beginning of the Age of Enlightenment down to our own day, the Galileo case has been a sort of “myth” in which the image fabricated out of the events is quite far removed from reality. In this perspective, the Galileo case was a symbol of the Catholic Church’s supposed rejection of scientific progress, or of “dogmatic” obscurantism opposed to the free search for truth.’

But surely the Holy Inquisition ushering the elderly and infirm Galileo in to inspect the instruments of torture in the dungeons of the Church not only admits but requires just such an interpretation… Censoring alternative views and threatening to torture their proponents betray a lack of faith in the very doctrine and parishioners that are ostensibly being protected. Why were threats and Galileo’s house arrest needed? Cannot truth defend itself in its confrontation with error?

[p 31]

spinning blue dot[31]

On belief in god(s)

What do we really want from philosophy and religion? Palliatives? Therapy? Comfort? Do we want reassuring fables or an understanding of our actual circumstances? Dismay that the Universe does not conform to our preferences seems childish.

But if our objective is deep knowledge rather than shallow reassurance, the gains from this new perspective far outweigh the losses. Once we overcome our fear of being tiny, we find ourselves on the threshold of a vast and awesome Universe that utterly dwarfs—in time, in space, and in potential—the tidy anthropocentric proscenium of our ancestors. We gaze across billions of light-years of space to view the Universe shortly after the Big Bang, and plumb the fine structure of matter. We peer down into the core of our planet, and the blazing interior of our star. We read the genetic language in which is written the diverse skills and propensities of every being on Earth. We uncover hidden chapters in the record of our own origins, and with some anguish better understand our nature and prospects. We invent and refine agriculture, without which almost all of us would starve to death. We create medicines and vaccines that save the lives of billions. We communicate at the speed of light, and whip around the Earth in an hour and a half. We have sent dozens of ships to more than seventy worlds, and four spacecraft to the stars. We are right to rejoice in our accomplishments, to be proud that our species has been able to see so far, and to judge our merit in part by the very science that has so deflated our pretensions…

There is in this Universe much of what seems to be design. Every time we come upon it, we breathe a sigh of relief. We are forever hoping to find, or at least safely deduce, a Designer. But instead, we repeatedly discover that natural processes… can extract order out of chaos, and deceive us into deducing purpose where there is none…. But, amid much elegance and precision, the details of life and the Universe also exhibit haphazard, jury-rigged arrangements and much poor planning. What shall we make of this: an edifice abandoned early in construction by the architect?

The evidence, so far at least and laws of Nature aside, does not require a Designer. Maybe there is one hiding, maddeningly unwilling to be revealed. Sometimes it seems a very slender hope.

The significance of our lives and our fragile planet is then determined only by our own wisdom and courage. We are the custodians of life’s meaning. We long for a Parent to care for us, to forgive us our errors, to save us from our childish mistakes. But knowledge is preferable to ignorance. Better by far to embrace the hard truth than a reassuring fable.

If we crave some cosmic purpose, then let us find ourselves a worthy goal…

The pioneering psychologist William James called religion a “feeling of being at home in the Universe.” Our tendency has been… to pretend that the Universe is how we wish our home would be, rather than to revise our notion of what’s homey so it embraces the Universe. If, in considering James’ definition, we mean the real Universe, then we have no true religion yet.

[p 33-38, 137]

spinning blue dot[38]

Aliens conclude that (homeless) cars are Earth’s dominant life-forms

When you take pictures at a meter resolution or better, you find that the crisscrossing straight lines within the cities and the long straight lines that join them with other cities are filled with streamlined, multicolored beings a few meters in length, politely running one behind the other, in long, slow orderly procession. They are very patient. One stream of beings stops so another stream can continue at right angles. Periodically, the favor is returned. At night, they turn on two bright lights in front so they can see where they’re going. Some, a privileged few, go into little houses when their workday is done and retire for the night. Most are homeless and sleep in the streets.

At last! You’ve detected the source of all the technology. the dominant life-forms on the planet. The streets of the cities and the roadways of the countryside are evidently built for their benefit. You might believe that you were really beginning to understand life on Earth. And perhaps you’d be right.

[p 42-43]

spinning blue dot[46]

Would an alien visiting Earth think it had intelligent life?

[Y]ou’ve found manifestations of intelligent beings… Surely this planet is worth a longer and more detailed study…

Looking down on the planet, you uncover new puzzles. All over the Earth, smokestacks are pouring carbon dioxide and toxic chemicals into the air… If this keeps up, the temperature of the planet is going to increase. Spectroscopically, you discover another class of molecules being injected into the air, the chlorofluorocarbons. Not only are they greenhouse gases, but they are also devastatingly effective in destroying the protective ozone layer.

You look more closely at the center of the South American continent, which—as you know by now—is a vast rain forest. Every night you see thousands of fires. In the daytime, you find the region covered with smoke. Over the years, all over the planet, you find less and less forest and more and more scrub desert.

You look down on the large island of Madagascar. The rivers are colored brown, generating a vast stain in the surrounding ocean. This is topsoil being washed out to sea at a rate so high that in another few decades there will be none left. The same thing is happening, you note, at the mouths of rivers all over the planet.

But no topsoil means no agriculture. In another century, what will they eat? What will they breathe? How will they cope with a changing and more dangerous environment?

From your orbital perspective, you can see that something has unmistakably gone wrong. The dominant organisms, whoever they are—who have gone to so much trouble to rework the surface—are simultaneously destroying their ozone layer and their forests, eroding their topsoil, and performing massive, uncontrolled experiments on their planet’s climate. Haven’t they noticed what’s happening? Are they oblivious to their fate? Are they unable to work together on behalf of the environment that sustains them all?

Perhaps, you think, it’s time to reassess the conjecture that there’s intelligent life on Earth.

[p 43-44]

spinning blue dot[55]

Voyager and the cost-effectiveness of robotic planetary exploration

The two Voyager robots have explored four planets [Jupiter, Saturn, Uranus, and Neptune] and nearly sixty moons… They are still returning reams of data…

The Voyagers embody the technology of the early 1970s; if spacecraft were designed for such a mission today, they would incorporate stunning advances in artificial intelligence, in miniaturization, in data-processing speed, in the ability to self-diagnose and repair, and in the propensity to learn from experience They would also be much cheaper….

It is conventional wisdom now that anything built by the government will be a disaster. But the two Voyager spacecraft were built by the government (in partnership with that other bugaboo, academia). They came in at cost, on time, and vastly exceeded their design specifications [“The Voyagers were guaranteed to work only until the Saturn encounter”] —as well as the fondest dreams of their makers. Seeking not to control, threaten, wound, or destroy, these elegant machines represent the exploratory part of our nature set free to roam the Solar System and beyond… Voyager cost each American less than a penny a year from launch to Neptune encounter. Missions to the planets are one of those things—and I mean this not just for the United States, but for the human species—that we do best.

[p 10, 52-53]

spinning blue dot[65]

Numerology is so ridiculous

[Long ago,] people all over the world understood that five, no more, of the bright points of light that grace the night sky break lockstep with the others… Sharing the odd apparent motion of these planets were the Sun and Moon, making seven wandering bodies in all. These seven were important to the ancients, and they named them after… the chief gods…

When it got to be time to design the week—a period of time, unlike the day, month, and year, with no intrinsic astronomical significance—it was assigned seven days, each named after one of the seven anomalous lights in the night sky…

This collection of seven gods, seven days, and seven worlds the Sun, the Moon, and the five wandering planets entered the perceptions of people everywhere. The number seven began to acquire supernatural connotations… Even in our time these associations linger.

The existence even of the four satellites of Jupiter that Galileo discovered—hardly planets—was disbelieved on the grounds that it challenged the precedence of the number seven. As acceptance of the Copernican system grew, the Earth was added to the list of planets, and the Sun and Moon were removed. Thus, there seemed to be only six planets (Mercury, Venus, Earth, Mars, Jupiter, and Saturn). So learned academic arguments were invented showing why there had to be six. For example, six is the first “perfect” number, equal to the sum of its divisors… there were only six days of creation…

[T]his self-indulgent mode of thinking spilled over from planets to moons. The Earth had one moon; Jupiter had the four Galilean moons. That made five. Clearly one was missing… When Huygens discovered Titan in 1655, he… actually gave up searching for other moons…

G. D. Cassim of the Paris Observatory discovered [Iapetus and Rhea.]  Cassim added up the number of planets (six) and the number of satellites (eight) and got fourteen. Now it so happened that the man who built Cassim’s observatory for him and paid his salary was Louis XIV of France… Cassim then backed off from looking for more moons…

[p 62-64]

spinning blue dot[76]

Mixed feelings about Apollo

Kennedy’s science advisor, Jerome Wiesner, later told me he had made a deal with the President: If Kennedy would not claim that Apollo was about science, then he. Wiesner, would support it. So if not science, what?… Nonaligned nations would be tempted to drift toward the Soviet Union if it was ahead in space exploration, if the United States showed insufficient “national vigor.” … Sending people to orbit the Earth or robots to orbit the Sun requires rockets—big, reliable, powerful rockets. Those same rockets can be used for nuclear war…of all the ways of demonstrating rocket potency, this one works best. It was a rite of national manhood; the shape of the boosters made this point readily understood without anyone actually having to explain it…

For me, the most ironic token of that moment in history is the plaque signed by President Richard M. Nixon that Apollo 11 took to the Moon. It reads: “We came in peace for all mankind.” As the United States was dropping 7½ megatons of conventional explosives on small nations in Southeast Asia, we congratulated ourselves on our humanity: We would harm no one on a lifeless rock…

Apollo 17 was the first to carry a scientist. As soon as he got there, the program was canceled. The first scientist and the last human to land on the Moon were the same person. The program had already served its purpose that July night in 1969…

Nevertheless, good space science was done…  If not for Apollo—and, therefore, if not for the political purpose it served—I doubt whether the historic American expeditions of exploration and discovery throughout the Solar System would have occurred, The Mariners, Vikings, Pioneers, Voyagers ,and Galileo are among the gifts of Apollo…

Apollo conveyed a confidence, energy, and breadth of vision that did capture the imagination of the world… For the first time, the inhabitants of Earth could see their world from above—the whole Earth, the Earth in color, the Earth as an exquisite spinning white and blue ball set against the vast darkness of space. Those images helped awaken our slumbering planetary consciousness. They provide incontestable evidence that we all share the same vulnerable planet. They remind us of what is important and what is not. They were the harbingers of Voyager’s pale blue dot.

[p 100-102]

spinning blue dot[88]

To understand Earth’s environment, we must also understand our neighbors

[T]he connection between exploring other worlds and protecting this one is most evident in the study of Earth’s climate and the burgeoning threat to that climate that our technology poses. Other worlds provide vital insights about what dumb things not to do on Earth…

Who discovered that CFCs posed a threat to the ozone layer? Was it the principal manufacturer, the DuPont Corporation, exercising corporate responsibility? Was it the Environmental Protection Agency protecting us? …No, it was two Ivory-tower, white-coated university scientists working on something else—Sherwood Rowland and Mario Molina of the University of California, Irvine… No one instructed them to look for dangers to the environment. They were pursuing fundamental research…Their names should be known to every schoolchild.

In their original calculations, Rowland and Molina used rate constants of chemical reactions involving chlorine and other halogens that had been measured in part with NASA support. Why NASA? Because Venus has chlorine and fluorine molecules in its atmosphere, and planetary aeronomers had wanted to understand what’s happening there.

Confirming theoretical work on the role of CFCs in ozone depletion was soon done by a group led by Michael McElroy at Harvard. How is it they had all these branching networks of halogen chemical kinetics in their computer ready to go? Because they were working on the chlorine and fluorine chemistry of the atmosphere of Venus…

Suppose that we have a three-dimensional general circulation computer model of the Earth’s climate… One way to test this program is to apply it to the very different climates of other planets… In fact, climate models now in use do very well in predicting from first principles of physics the climates on Venus and Mars.

Some of the most important recent work on global warming has been done by James Hansen and his colleagues at the Goddard Institute for Space Sciences, a NASA facility in New York City… How did Hansen get interested in the greenhouse effect in the first place? His doctoral thesis… was about Venus…

I know many other instances where scientists who first tried to puzzle out the atmospheres of other worlds are making important and highly practical discoveries about this one…

Planetary science fosters a broad interdisciplinary point of view that proves enormously helpful in discovering and attempting to defuse these looming environmental catastrophes. When you cut your teeth on other worlds, you gain a perspective about the fragility of planetary environments and about what other, quite different, environments are possible. There may well be potential global catastrophes still to be uncovered. If there are, I bet planetary scientists will play a central role in understanding them.

Of all the fields of mathematics, technology, and science, the one with the greatest international cooperation (as determined by how often the co-authors of research papers hail from two or more countries) is the field called “Earth and space sciences.” Studying this world and others, by its very nature, tends to be non-local, non-nationalist, non-chauvinist… Almost always, they enter for other reasons, and then discover that splendid work, work that complements their own, is being done by researchers in other nations; or that to solve a problem, you need data or a perspective (access to the southern sky, for example) that is unavailable in your country. And once you experience such cooperation—humans from different parts of the planet working in a mutually intelligible scientific language as partners on matters of common concern—it’s hard not to imagine it happening on other, nonscientific matters…

When I look at the evidence, it seems to me that planetary exploration is of the most practical and urgent utility for us here on Earth. Even if we were not roused by the prospect of exploring other worlds, even if we didn’t have a nanogram of adventuresome spirit in us, even if we were only concerned for ourselves and in the narrowest sense, planetary exploration would still constitute a superb investment.

[p 104-108]

spinning blue dot[90]

The only real purpose of a space station

The only tangible and coherent goal of a space station is eventual human missions to near-Earth asteroids, Mars, and beyond. Historically NASA has been cautious about stating this fact clearly, probably for fear that members of Congress will throw up their hands in disgust, denounce the space station as the thin edge of an extremely expensive wedge, and declare the country unready to commit to launching people to Mars. In effect, then, NASA has kept quiet about what the space station is really for.

[p 119]

spinning blue dot[93]

The “spinoff” sales pitch is disingenuous

It is alleged that “spinoff” will transpire—huge technological benefits that would otherwise fail to come about—thereby improving our international competitiveness and the domestic economy. But this is an old argument: Spend $80 billion (in contemporary money) to send Apollo astronauts to the Moon, and we’ll throw in a free stickless frying pan. Plainly, if we’re after frying pans, we can invest the money directly and save almost all of that $80 billion.

The argument is specious for other reasons as well, one of which is that DuPont’s Teflon technology long antedated Apollo. The same is true of cardiac pacemakers, ballpoint pens, Velcro, and other purported spinoffs of the Apollo program. (I once had the opportunity to talk with the inventor of the cardiac pacemaker, who himself nearly had a coronary accident describing the injustice of what he perceived as NASA taking credit for his device.) If there are technologies we urgently need, then spend the money and develop them. Why go to Mars to do it?

Of course it would be impossible for so much new technology as NASA requires to be developed and not have some spillover into the general economy, some inventions useful down here. For example, the powdered orange juice substitute Tang was a product of the manned space program, and spinoffs have occurred in cordless tools, implanted cardiac defibrillators, liquid-cooled garments, and digital imaging—to name a few. But they hardly justify human voyages to Mars or the existence of NASA.

We could see the old spinoff engine wheezing and puffing in the waning days of the Reagan-era Star Wars office. Hydrogen bomb-driven X-ray lasers on orbiting battle stations will help perfect laser surgery, they told us. But if we need laser surgery, if it’s a high national priority, by all means let’s allocate the funds to develop it. just leave Star Wars out of it. Spinoff justifications constitute an admission that the program can’t stand on its own two feet, cannot be justified by the purpose for which it was originally sold.

[p 127-128]

spinning blue dot[123]

Deflecting asteroids – we’re not ready for the responsibility

[I]f you can reliably deflect a threatening worldlet so it does not collide with the Earth, you can also reliably deflect a harmless worldlet so it does collide with the Earth. Suppose you had a full inventory, with orbits, of the estimated 300,000 near-Earth asteroids larger than 100 meters—each of them large enough, on impacting the Earth, to have serious consequences. Then, it turns out, you also have a list of huge numbers of inoffensive asteroids whose orbits could be altered with nuclear warheads so they quickly collide with the Earth…

Tracking asteroids and comets is prudent, it’s good science, and it doesn’t cost much. But, knowing our weaknesses, why would we even consider now developing the technology to deflect small worlds?…

If we’re too quick in developing the technology to move worlds around, we may destroy ourselves; if we’re too slow, we will surely destroy ourselves. The reliability of world political organizations and the confidence they inspire will have to make significant strides before they can be trusted to deal with a problem of this seriousness…

Since the danger of misusing deflection technology seems so much greater than the danger of an imminent impact, we can afford to wait, take precautions, rebuild political institutions—for decades certainly, probably centuries. If we play our cards right and are not unlucky, we can pace what we do up there by what progress we’re making down here…

The asteroid hazard forces our hand. Eventually, we must establish a formidable human presence throughout the inner Solar System. On an issue of this importance I do not think we will be content with purely robotic means of mitigation. To do so safely we must make changes in our political and international systems.

[p 146-150]

spinning blue dot[97]

The search for extraterrestrial life

If I had to guess… I would guess that the Universe is filled with beings far more intelligent, far more advanced than we are.

We are now, on an unprecedented scale, listening for radio signals from possible other civilizations in the depths of space. Alive today is the first generation of scientists to interrogate the darkness. Conceivably it might also be the last generation before contact is made—and this the last moment before we discover that someone in the darkness is calling out to us…

In 1983 Ann Druyan and I suggested to the filmmaker Steven Spielberg that this was an ideal project for him to support… With his initial support through The Planetary Society, Project META began… The META radio telescope at Harvard, Massachusetts, is 26 meters (84 feet) in diameter. Each day, as the Earth rotates the telescope beneath the sky, a swath of stars narrower than the full moon is swept out and examined. Next day, it’s an adjacent swath. Over a year, all of the northern sky and part of the southern is observed. An identical system, also sponsored by The Planetary Society, is in operation just outside Buenos Aires, Argentina, to examine the southern sky. So together the two META systems have been exploring the entire sky…

Horowitz and I have published detailed results from five years of full-time searching with Project META and two years of follow-up. We can’t report that we found a signal from alien beings. But we did find something puzzling, something that for me in quiet moments, every now and then, raises goose bumps…

Any strong narrow-band signal that remains in a single channel we take very seriously… A few dozen signals survive the culling. These are subjected to further scrutiny…

What’s left—the strongest candidate signals after three surveys of the sky—are 11 “events.” They satisfy all but one of our criteria for a genuine alien signal. But the one failed criterion is supremely important: Verifiability. We’ve never been able to find any of them again… [P]ossibly, this is the effect of twinkling… Imagine a radio signal that’s a little below the strength that we could otherwise detect on Earth. Occasionally the signal will by chance be temporarily focused, amplified, and brought within the detectability range of our radio telescopes. The interesting thing is that the lifetimes of such brightening, predicted from the physics of the interstellar gas, are a few minutes—and the chance of reacquiring the signal is small. We should really be pointing steadily at these coordinates in the sky, watching them for months.

Despite the fact that none of these signals repeats, there’s an additional fact about them that, every time I think about it, sends a chill down my spine: 8 of the 11 best candidate signals lie in or near the plane of the Milky Way Galaxy. The five strongest are in the constellations Cassiopeia, Monoceros, Hydra, and two in Sagittarius… The probability that this correlation with the galactic plane is due merely to chance is less than half a percent…

Without repeatable signals, though, there’s no way we can conclude that we’ve actually found extraterrestrial intelligence.

Or maybe the events we’ve found are caused by some new kind of astrophysical phenomenon, something that nobody has thought of yet, by which not civilizations, but stars or gas clouds (or something) that do lie in the plane of the Milky Way emit strong signals in bafflingly narrow frequency bands…

Would I like to believe that with META we’ve detected transmissions from other civilizations out there in the dark, sprinkled through the vast Milky Way Galaxy? You bet… In our fascination with SETI, we might be tempted, even without good evidence, to succumb to belief but this would be self-indulgent and foolish. We must surrender our skepticism only in the face of rock-solid evidence. Science demands a tolerance for ambiguity. Where we are ignorant, we withhold belief. Whatever annoyance the uncertainty engenders serves a higher purpose: It drives us to accumulate better data. This attitude is the difference between science and so much else. Science offers little in the way of cheap thrills. The standards of evidence are strict. But when followed they allow us to see far, illuminating even a great darkness.

[p 24, 163-170]

spinning blue dot[102]

The book’s main thesis: the time is NOW to begin settling other planets — starting with Mars

This is the first moment in the history of our planet when any species, by its own voluntary actions, has become a danger to itself—as well as to vast numbers of others… Is it not likely that other dangers of our own making are yet to be discovered, some perhaps even more serious? …Since, in the long run, every planetary society will be endangered by impacts from space, every surviving civilization is obliged to become spacefaring—not because of exploratory or romantic zeal, but for the most practical reason imaginable: staying alive…

Of course we must keep our planet habitable—not on a leisurely timescale of centuries or millennia, but urgently, on a timescale of decades or even years. This will involve changes in government, in industry, in ethics, in economics, and in religion. We’ve never done such a thing before, certainly not on a global scale. It may be too difficult for us…

However, we humans also have a history of making long-lasting social change that nearly everyone thought impossible. Since our earliest days, we’ve worked not just for our own advantage but for our children and our grandchildren… We seem, these days, much more willing to recognize the dangers before us than we were even a decade ago. The newly recognized dangers threaten all of us equally. No one can say how it will turn out down here…

The more of us beyond the Earth, the greater the diversity of worlds we inhabit, the more varied the planetary engineering, the greater the range of societal standards and values—then the safer the human species will be…

To take out this insurance policy is not very expensive, not on the scale on which we do things on Earth. It would not even require doubling the space budgets of the present spacefaring nations (which, in all cases, are only a small fraction of the military budgets…) We could soon be setting humans down on near-Earth asteroids and establishing bases on Mars. We know how to do it, even with present technology, in less than a human lifetime. And the technologies will quickly improve. We will get better at going into space. A serious effort to send humans to other worlds is relatively so inexpensive on a per annum basis that it cannot seriously compete with urgent social agendas on Earth.

…[O]n behalf of Earthlife, I urge that, with full knowledge of our limitations, we vastly increase our knowledge of the Solar System and then begin to settle other worlds.

These are the missing practical arguments: safeguarding ‘the Earth from otherwise inevitable catastrophic impacts and hedging our bets on the many other threats, known and unknown, to the environment that sustains us. Without these arguments, a compelling case for sending humans to Mars and elsewhere might be lacking. But with them—and the buttressing arguments involving science, education, perspective, and hope—I think a strong case can be made. If our long-term survival is at stake, we have a basic responsibility to our species venture to other worlds.

[p 172-176]

spinning blue dot

But wasn’t it science that got us INTO this mess?

All our self-inflicted environmental problems, all our weapons of mass destruction are products of science and technology. So, you might say, let’s just back off from science and technology. Let’s admit that these tools are simply too hot to handle. Let’s create a simpler society, in which no matter how careless or short-sighted we are, we’re incapable of altering the environment on a global or even on a regional scale. Let’s throttle back to a minimal, agriculturally intensive technology, with stringent controls on new knowledge… So controlled a society must grant great powers to the elite that does the controlling, inviting flagrant abuse and eventual rebellion. It’s very hard—once we’ve seen the riches, conveniences, and lifesaving medicines that technology offers—to squelch human inventiveness and acquisitiveness. And while such a devolution of the global civilization, were it possible, might conceivably address the problem of self-inflicted technological catastrophe, it would also leave us defenseless against eventual asteroidal and cometary impacts…

Science cuts two ways, of course; its products can be used for both good and evil. But there’s no turning back…

[p 178-179]

2 thoughts on “Carl Sagan’s “Pale Blue Dot”: Still Timely Excerpts

  1. Pingback: Worst Carl Sagan Day Ever – Under the Greenwood Tree

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