Starry Messenger: Cosmic Perspectives on Civilization

by Neil deGrasse Tyson

You develop an instant global consciousness, a people orientation, an intense dissatisfaction with the state of the world, and a compulsion to do something about it. From out there on the Moon, international politics look so petty. You want to grab a politician by the scruff of the neck and drag him a quarter of a million miles out and say, “Look at that, you son of a bitch.” —Edgar D. Mitchell, Apollo 14 astronaut

We’ve lost all sight of what distinguishes facts from opinions. We’re quick with acts of aggression and slow with acts of kindness.

Galileo’s freshly perfected telescope revealed a universe unlike anything people presumed to be true. Unlike anything people wanted to be true. Unlike anything people dared say was true.

We possess different values, different priorities, and different understandings of all that unfolds around us. We see the world differently from one another, and by doing so, we construct tribes based on who looks like us, who prays to the same gods as we do, and who shares our moral code. Given the longtime Paleolithic isolation within our species, perhaps we should not be surprised by what evolution has wrought. Groupthink, even when it defies rational analysis, may have conferred survival advantages to our ancestors.

What is civilization, if not what humans have built for themselves as a means to transcend primal urges and as a landscape on which to live, work, and play.

scientists are not in search of each other’s opinions. We’re in search of each other’s data.

Do whatever it takes to avoid fooling yourself into believing that something is true when it is false, or that something is false when it is true.

The scientific method

“The greatest deception men suffer is from their own opinion.”

Leonardo Da Vinci

Healthy disagreement is a natural state on the bleeding edge of discovery.

Objective truths apply to all people, places, and things, as well as all animals, vegetables, and minerals. Some of these truths apply across all of space and time. They are true even when you don’t believe in them.

Objective truths, established by repeated experiments that give consistent results, are not later found to be false. No need to revisit the question of whether Earth is round; whether the Sun is hot; whether humans and chimps share more than 98 percent identical DNA; or whether the air we breathe is 78 percent nitrogen.

The only times science cannot assure objective truths is on the pre-consensus frontier of research. The only era in which science could not assure objective truths was before the seventeenth century, back when our senses—inadequate and biased—were the only tools at our disposal to inform us of the natural world.

Objective truths of science are not founded in belief systems. They are not established by the authority of leaders or the power of persuasion. Nor are they learned from repetition or gleaned from magical thinking. To deny objective truths is to be scientifically illiterate, not to be ideologically principled.

Personal truths are what you’re sure is true, even if you can’t—especially if you can’t—prove it.

Personal truths are what you may hold dear but have no real way of convincing others who disagree, except by heated argument, coercion, or force. These are the foundations of most people’s opinions and are normally harmless when kept to yourself or argued over a beer.

Differences in opinion enrich the diversity of a nation, and ought to be cherished and respected in any free society, provided everyone remains free to disagree with one another and, most importantly, everyone remains open to rational arguments that could change your mind.

Social, political, or legislative attempts to require that everybody agree with your personal truths are ultimately dictatorships.

few of us have ever seen a bar fight break out between two people drinking wine. Gin, maybe. Whisky, definitely. Chardonnay, no. Imagine the absurdity of such a line in a movie script: “I’m going to kick your ass, but only after I’m done sipping my Merlot!”

Often the less actual evidence that exists in support of an ideology, the more likely a person is willing to die for the cause. Aryan Germans of the 1930s weren’t born thinking they were the master race to all other people in the world. They had to be indoctrinated. And they were. By an efficient, lubricated political machine. By 1939 and the start of World War II, millions were ready to die for it—and did.

Cloud taxonomy fascinated the Scottish meteorologist Ralph Abercromby, and in 1896 he documented as many as he could around the world, creating a numerical sequence for them. You guessed it. Cumulonimbus clouds landed at number 9, unwittingly seeding the everlasting concept of being on “cloud nine” when in a blissful state.

(NGC 6543),

(NGC 1952),

Earth is commonly thought to be a haven for life—nurtured by the maternal instincts of Mother Nature. That’s true to an extent. Earth has been teeming with life ever since it could support life. Yet Earth is also a giant killing machine. More than 99 percent of all species that ever lived are now extinct10 from forces such as regional and global climate change as well as environmental assaults

Smallpox, malaria, and the bubonic plague together have killed upwards of 1.5 billion people throughout time, worldwide. That toll far exceeds all deaths from all armed conflicts in the history of our species. Nature has killed more of us than we have of ourselves.

Evidence shows that nature doesn’t actually care about our health or longevity.

there is no hint from space that anyone or anything in the universe will arrive to save us from Earth, or from ourselves. It is we alone who care about us.

Medical researchers develop vaccines to protect us from lethal viruses, and medicines to ward off bacteria and parasites. Architects and builders create homes and shelters to protect us from catastrophic weather. In the future, astrodynamicists will develop space systems that deflect the trajectories of killer asteroids headed our way. Contrary to implicit tenets of the green movement, not all that is natural is beautiful, and not all that is beautiful is natural.

Odd that these same skeptics hardly ever wonder whether we should do both: explore space and fix society’s problems. The world’s list of challenging problems long predates anybody ever spending a dime on space.

One final note on our troglodytes: They breathed fresh air. They drank clean water. They ate organic plants and free-range animals—yet their staggeringly high infant mortality left them with an average life expectancy of barely thirty years. Modern science matters.

we knew more about the Moon before we visited for the first time than any fifteenth or sixteenth-century explorer knew about their destinations. We knew more about the surface of Mars and where to land our rovers than the twelfth and thirteenth-century Polynesian wayfinders knew about the Pacific islands that awaited them, far beyond their oceanic horizons.

Part of the problem is that we’re all wired with linear minds, leaving us prone to think small. It’s not our fault. We think in additives and multiples, with no evolutionary pressure to think in exponentials. An exponential is a number raised to the power of another number. When you do that, quantities and rates described by them rise (or shrink) faster than our normal capacity to comprehend. Consider this simple example: You can choose to receive $5 million now or instead receive a penny a day doubled for a month. Most people would take the $5 million and run, avoiding the pennies altogether. Let’s first think it through. That’s a penny today. Then two pennies tomorrow. Four pennies the next day. Eight pennies the day after that, and so on. How rich are you at the end? If you do the math, on the thirty-first day you will be handed $10,737,418.24. And the sum of pennies from your previous thirty days brings your total to $21,474,836.47.

We think of Darwinian evolution as imperceptibly slow. That’s because we live, at most, 100 years, and our brain wiring resists the fact that speciation can take thousands and even millions of times longer than our lifetime to unfold.

Even the Apollo 11 mission to the Moon planted a flag—the American flag. Although the plaque that accompanied it was unlike any other in the history of hegemony: HERE MEN FROM THE PLANET EARTH FIRST SET FOOT UPON THE MOON JULY 1969, A.D. WE CAME IN PEACE FOR ALL MANKIND

With systems in place to disseminate thought, such as scientific conferences, peer-reviewed journals, and patent filings, every next generation can use discoveries of the previous generation as fresh starting points. No reinventing the wheel. No wasted efforts. This blunt and obvious fact carries profound consequences. It means knowledge grows exponentially, not linearly, rendering our brains hopeless in our attempts to predict the future based on the past.

How often have we all heard the phrase, “the miracles of modern medicine”? Now look back fifty years at the doctor’s bag with scary tools and questionable cures and you take smug delight in being alive today instead of at any other time.

From 1930 to 1960, we go from airplanes flying at speeds of a few hundred miles per hour, to breaking the sound barrier in 1947, to the dawn of the space age, inspired in part by ballistic rockets developed as wartime weapons. In 1957 the Soviet Union launches Sputnik, Earth’s first artificial satellite, which travels at 17,500 mph in low-Earth orbit. In 1958, the world’s first commercial jet airplane—the Boeing 707, flown by Pan American Airways—enjoys a wingspan wider than the distance flown by the Wright brothers’ first flight in 1903.

The commercialization of the transistor allows consumer electronics to miniaturize, transforming audiovisual equipment from heavy, floor-mounted living room furniture to what you carry in your pocket.

By 2000, searchable websites and e-commerce are commonplace, and everyone with a computer and access to the internet obtains an email address. Early in this period, mobile phones had become standard for anyone leaving the house, but beginning in 2007 are rapidly replaced by the pocket-size smartphone, granting full access to music, media, and the internet.

The smartphone may be the single greatest invention in the history of inventions. In 2020 there are three billion of them in a world of eight billion people. Before 2007 there were zero. Show a smartphone to anyone in 1990, and they may just resurrect witch-burning laws to eradicate your magic.

You know you’re living in the future when you can board a hundred-ton pressurized aluminum tube with wings, fly smoothly in a cushioned chair at 500 miles per hour, 31,000 feet above Earth’s surface, and while crossing the continent, get served a pasta dinner and a mixed drink by someone whose job, in part, is to make you comfortable. And for most of the trip you surf the internet, watch any one of a hundred movies, only to land safely and smoothly a few hours later and complain that the marinara sauce was not to your liking.

the wisdom of elders carries only marginal sway, which accounts for much of the tension that roils multigenerational Thanksgiving dinners. Their advice is predictably out of touch for what your college major should be, what jobs you should seek, what cars you should buy, what medicines you should take, what jokes you should tell, and what foods you should eat.

your elders may carry more wisdom than you for navigating human sentiments such as love, kindness, integrity, and honor, which remain among the few constants of the world.

A fan once asked twentieth-century sci-fi novelist Ray Bradbury why he imagined bleak futures. Is civilization doomed? He replied, “No. I write about these futures so that you know to avoid them.”

With only one or two human-made structures visible from Earth orbit, everything else that divides us—national borders, politics, languages, skin color, who you worship—is invisible to you.

If the Space Shuttle and the International Space Station orbit between 1 and 1.3 centimeters above the schoolroom globe, find the Moon in the next classroom, ten meters away. That’s why it takes only eight minutes for a rocket to reach Earth orbit, but a full three days for the Apollo rockets to reach the Moon.

“Crying Indian” public service TV commercial

full moons rise at sunset and set at sunrise, and the physics of reflectivity makes them six times (!) brighter than half-moons, so they provide an excellent guiding light throughout the night.

The art of asking questions represents an important dimension of science literacy. How you think and how you query nature matter more than what you know. Often the answers reveal themselves simply by asking the right questions in the right sequence.

How long is the human gestation period? Doctors will tell you 280 days (40 weeks), which is not entirely true. That’s the count of days from the last menstrual cycle. Hardly anybody gets pregnant then. You probably got pregnant when you ovulated, two weeks later. So the actual time to make a full-term human baby comes to 280 days − 14 days = 266 days. Now let’s ask about the time it takes for the Moon to cycle through its phases—full Moon to full Moon. You can look that up: it averages 29.53 days. Nine of these cycles comes to 266 days. That’s interesting. A full-term baby takes about nine cycles of the Moon to develop in the womb. So to be born under a full Moon, romantic as it is, simply means you were likely conceived under one, romantic as it was.

In the Earth-Moon system, the side of Earth facing the Moon is closer, so it feels a slightly stronger force of gravity than the side facing away. This creates a stretching force across Earth’s diameter, most visible in our oceanic tides, but the solid earth experiences it too. Notice that this description of Moon tides on Earth makes no mention of the Moon’s phase. That’s because the strength of the Moon’s tides has nothing to do with the Moon’s phase. Full Moons get the highest tides not because of the Moon but because of the Sun. The Sun’s tides on Earth are about one-third the strength of the Moon’s tides, yet hardly anybody talks about them. During full Moon, high Sun tides add directly to high Moon tides, giving the false impression that the full Moon imparts extra gravitational influence.