Wednesday, April 30, 2014

Spacecraft carry Earth's good will [Reprise]

[This musing first appeared in The Boston Globe, April 30, 2002.—Tom.]

Remember 1972? Led Zeppelin. Carly Simon. “The Godfather.” “Hawaii Five-O.” George Wallace shot. Watergate. Bombing raids on North Vietnam.

Murders at the Summer Olympics. Mark Spitz. Pioneer 10.

Pioneer 10?

The little spacecraft with the big antenna blasted off March 2, 1972, on top of an Atlas-Centaur rocket. Pioneer 10 was going to be the first human artifact to leave the solar system.

The news media was atwitter because of the plaque affixed to the side of the craft, which Carl Sagan helped design, meant as an Earthly greeting to whatever alien civilization the spacecraft might someday encounter.

There were protests, as I recall, because the plaque depicted a nude human male and female (“Dirty pictures,” said letters to editors). But most objections were not to the nudity—after all, this was at the height of the Sexual Revolution—but because some people thought the images were politically incorrect.

It was the male who raised his hand in greeting, not the female (male chauvinism!). The male’s genitals were shown, but not the female’s (sexism!). And the figures—deliberately designed to be multiracial—were thought by some to be too Caucasian, by others too Negroid (racism!).

Those were highly charged times, and today the controversies seem rather quaint. After all, the chance that an intelligent alien civilization will ever see the plaque is exceedingly slim. Pioneer 10 is heading in the direction of the constellation Taurus, but won’t pass the nearest star there for 2 million years.

In fact, the spacecraft is not yet in true interstellar space. It passed the orbit of Pluto in 1983, and thus left the solar system by some accounts, but it still lies within the influence of the Sun’s magnetic field and outward flow of solar particles. Sometime in the next few years, it will leave even that gentle touch of the Sun behind.

Thirty years into its voyage, Pioneer 10 is more than 7 billion miles away, and still in radio contact with Earth. Scientists last contacted the craft on March 2 of this year, beaming a signal to the spaceship’s receiver and getting a response. The round-trip communication took 22 hours, traveling at the speed of light. By comparison, a radio signal takes just 8 minutes to travel from the Earth to the sun.

Of the craft’s 11 scientific instruments, only one, a Geiger Tube Telescope, is still working.

Pioneer 10 is nuclear powered, so there’s no problem of batteries running out, but it’s something of a miracle that the spacecraft has not yet cut its electronic umbilical cord to Earth. Its sister ship, Pioneer 11, launched in 1973 and hot on the tail of Pioneer 10, has been out of touch since 1995.

I love thinking of that chunk of human engineering drifting in deep space, heading for the stars, never to return, its radio squeaking a barely detectable homesick cry, those little naked figures affixed to its side facing the unfathomable gulf between the stars, the male’s hand raised in hopeful greeting.

The craft was launched in turbulent times, wonderful and terrible.

But most of all those times were hopeful. The peace movement was in full swing, with its dream of global harmony. Ecology and green politics.

Women’s liberation. Civil rights. The Peace Corps. Liberation theology. Flower power.

For all of the chaos that swirled about us, there was a dream that things could be better, that all humans could live in peace and equality, irrespective of gender, race, culture or religion. The young, especially, were convinced that the dawning of the Age of Aquarius meant an end to ancient animosities and injustices.

They were wrong, of course. Greed, hatred and intolerance are still with us. Perhaps they will always be with us. Perhaps they are embedded in our genes.

But the dream lives on, and thankfully so. We know we are not prisoners of our genes, and that we can rise above our baser instincts if only we can rally ourselves to try. We hold to the hope that on this tiny planet of a yellow star in a typical corner of the Milky Way Galaxy, we might yet create an oasis of creaturely order that is a model for the universe.

Pioneer 10 carries that hope into interstellar space. With Pioneer 11 and Voyagers 1 and 2, which also carry messages, it is an emissary of our best natures. The Voyagers bear musical selections from different cultures and eras, and spoken greetings from humans in 55 languages. That magnanimity of spirit was typical of the era in which the spacecraft were launched. Let us hope we can become worthy of the self-image we sent to the stars.

[2014 Update: Scientists last made contact with Pioneer 10 on January 23, 2003. Today, the spacecraft is estimated to be approximately 110 AU from the Earth.—Tom.]

Tuesday, April 29, 2014

Seeking order in the natural order [Reprise]

[This musing first appeared in The Boston Globe, April 29, 1996.—Tom.]

It is a popular misconception that evolution is “just a theory.”

On the contrary, the evidence for the development of life over billions of years by common descent from simple ancestors is overwhelming. So overwhelming that most biologists and geologists would call evolution a “fact.”

The influential geneticist Theodosius Dobzhansky said “Nothing makes sense except in the light of evolution.” Nobel prize-winning biologist Peter Medewar said, “The alternative to thinking in evolutionary terms is not to think at all.”

What these two great biologists meant is that no other scientific theory presently offers a satisfactory framework for making sense of what we know about the world.

Here are some things that virtually all biologists hold to be true:
  • Life has developed on this planet over billions of years.
  • All living organisms share common ancestors.
  • Species come and go.
  • Natural selection, as understood by Darwin and subsequently extended by Mendel, Weismann and population geneticists such as Dobzhansky, helps shape the tree of life.

Beyond that, the story of life is up for grabs—and hotly debated by biologists. One important bone of contention: Is natural selection acting alone enough to explain the diversity and complexity of life on Earth?

Many biologists would say yes. However, a growing number of biologists question the exclusivity of natural selection as the driving force of evolution. Also at work, they maintain, are sources of natural order that exist in any complex, organized system.

One scientist who advances this view is Stuart Kauffman of the Santa Fe Institute in New Mexico. He has written a hefty, highly technical book called “The Origins of Order” to answer the question, “What are the sources of the overwhelming and beautiful order which graces the living world?”

Kauffman sets out to show that sources of self-organization exist throughout the natural world: The six-pointed snowflake and spherical drop of rain are simple examples. In highly organized systems, such as biological organisms, these natural sources of order drive nature towards ever more complex forms.

“None can doubt Darwin’s main idea,” Kauffman writes. “If we are to consider the implications of spontaneous order, we must certainly do so in the context of natural selection, since biology without it is unthinkable.”

But Darwin is not enough, he insists.

Life has not been cobbled together by natural selection acting on random mutations, says Kauffman. We are not Rube Goldberg machines slapped together piece by piece by evolution. Rather, life is “a natural expression of the stunning self-organization that abounds in very complex regulatory networks . . . order, vast and generative, arises naturally.”

In other words, we are more than the sum of our chemical parts. Life is an emergent phenomenon that arose when chemical systems on the early Earth increased beyond a “threshold of complexity.” The subsequent history of life unfolds at least partly as a consequence of complexity.

Kauffman and his colleagues use powerful computers to explore how complex interconnected systems behave. They have demonstrated how complex systems of simple elements can catalyze their own self-organization.

These computer simulations show intriguing parallels with the real-world history of life.

Kauffman thinks laws of self-organization lie at the heart of nature. If we can discover these laws, he says, we will understand how our bodies developed from a single fertilized egg, and how our species emerged over billions of years from prebiotic chemicals.

He is a long way from finding the laws he is looking for, but the results achieved so far hint at a direction-ality and inevitability to evolution that may not be fully accounted for by Darwinian natural selection.

Anyone who enjoys watching a brilliant mind at work/play should glance at Kauffman’s “The Origins of Order,” or read his popular book on the same subject, called “At Home in the Universe.” One catches a glimpse of the power of the mathematical way of thinking, and also of a necessary humility in the face of life’s greatest mysteries.

He writes: “Almost 140 years after Darwin’s seminal book, we do not understand the powers and limitations of natural selection, we do not know what kinds of complex systems can be assembled by an evolutionary process, and we do not even begin to understand how selection and self-organization work together to create the splendor of a summer afternoon in an Alpine meadow flooded with flowers, insects, worms, soil, other animals, and humans, making our worlds together.”

Kauffman is not stingy with words like “possibility,” “maybe,” “I do not know.” He knows we have only begun to understand our origins. He talks about “reinventing the sacred.” He offers a vision of creation worthy of the most resourceful Creator.

Monday, April 28, 2014

Galactic images [Reprise]

[This musing first appeared in The Boston Globe, April 28, 1986.—Tom.]

The cluster of white domes on Siding Spring Mountain in New South Wales, Australia, reminded me of the bulbs of the white amanita mushrooms that spring up overnight in the New England woodlands after an autumn rain.

I had traveled to Australia to look at Comet Halley. The comet was worth the long journey, but the observatories on Siding Spring Mountain were in many ways more exciting. The setting for this great scientific facility is spectacular. On every side of the mountain are the jagged volcanic peaks of the Warrumbungle Mountains, mantled with gum trees and bush birds. In the grassy valleys at the base of the mountains kangaroos and emus graze at dawn and sunset. Beyond the mountains the featureless outback reaches to the far horizon.

In the largest of the domes is housed the Anglo-Australian 3.9 meter telescope, one of the largest telescopes in the southern hemisphere. Another building contains the Australian Advanced Technology Telescope, a pioneer in the new economies that can be achieved in telescope design by exploiting the capabilities of high-speed computers. Other domes hold smaller instruments. It was in the dome that housed the British 1.2 meter Schmidt “camera” that I found what I was looking for.

The Schmidt telescope is engaged in a systematic photographic survey of the southern sky. The photographs are made on glass plates coated with emulsions created especially for astronomy. The glass plates are not much thicker than a thumbnail. They are thin so they can be bent to match the curved focal surface of the telescope. Each plate is about the size of this newspaper page and covers a part of the sky equal to the size of your palm held at arm’s length. A typical exposure lasts about one hour, during which time the telescope must be moved with extreme accuracy to compensate for the turning of the earth.

The telescope was designed to record much fainter stars and more distant galaxies than have ever been seen before. Each photograph contains between one million and ten million visible images. The images are sharp spots and fuzzy spots. The sharp spots are stars in our own Milky Way Galaxy. The fuzzy spots are mostly other galaxies, other island universes that contain as many as a trillion stars apiece. About half of the images on any single plate are galaxies.

I had the opportunity to examine several contact negatives with a magnifier. In the magnifier, the brightest of the fuzzy spots became spiral galaxies of dazzling detail. Many of the fuzzy spots were interacting galaxies, two or more great star systems locked in a spiral-distorting gravitational dance.

It would require almost 1800 of these photographs to cover the entire sky. On each plate there are recorded as many as a million galaxies. Each galaxy contains hundreds of billions of stars. Many of those stars, like our own sun, have planets. With the magnifier, I examined in a few minutes more worlds than my mind was capable of imagining.

What does it mean, this extravagant profusion of worlds? I had traveled halfway around one tiny planet to visit Siding Spring Mountain: It seemed an enormous distance. Traveling at the same speed, it would take me two trillion years to reach the nearest of the galaxies on the photographs, and to reach the most distant of the recorded galaxies would require a time greater than the age of the universe.

Often, when I am teaching about the universe of the galaxies, one of my students will say to me, “It all makes me feel so small.” I disagree. Every galaxy that is fixed on a photographic plate has become a permanent part of the human imagination. Through the agency of the telescopes on Siding Spring Mountain, and others like them throughout the world, the human mind has gone out to embrace the distant galaxies. We may be physically small compared to the galaxies, but our minds can be as large as the universe.

In cosmic time, the domes on Siding Spring Mountain sprang up as quickly as mushrooms. And they will disappear as quickly. Like mushrooms, they are part of the story of life in the universe, a universe that here—and probably elsewhere—has achieved self-consciousness.

As I examined the photographic negatives, this thought occurred to me: We are almost certainly not the brightest thing the universe has yet thrown forth, but we are certainly not small. Our imaginations are billions of light years wide. We can justifiably say with Shakespeare’s Miranda: “O, wonder! How many goodly creatures are there here! How beauteous mankind is! O brave new world that has such people in’t!”

Sunday, April 27, 2014

Light field

Click to enlarge Anne's Sunday illumination.

Saturday, April 26, 2014

A Brit bureaucrat enthralled with science [Reprise]

[This musing first appeared in The Boston Globe, April 26, 1999.—Tom.]

I don’t know if high school kids today read Samuel Pepys’ Diary. Back in the 50s even parochial school students were exposed to bits of the diary—mostly Pepys’ accounts of the Great London Fire of 1666 and the plague.

Pepys was a government bureaucrat, not a scientist. Nevertheless he was swept along by the excitement. He purchased every new science book that came off the press, and struggled to understand it. He bought a microscope and a telescope and almost every other clever device that defined the new experimental age. And he cultivated the friendship of scientists. In 1665 he was elected to membership in the Royal Society; later, he would be elected president.

What we saw of his diary was severely edited, as I discovered recently by plowing through it; there were almost ten years worth of entries and what seemed a zillion words. Most of what Pepys committed to paper was a record of his pursuit of pleasure—food, drink, music, plays and women. Especially women.

During the years of the diary, 1660–1669, most of London was pursuing pleasure, following the example of their fun-loving monarch, Charles II. The king’s pleasures were unabashedly public, his mistresses openly acknowledged. Pepys was less unabashed; he managed to keep his amorous adventures secret from his wife, at least until she caught him flagrante delicto with her “lady.”

Of course, no hint of Pepys’ hanky-panky appeared in our high school excerpts.

What makes the diary such compelling reading is the combination of private and public history. Pepys was a man about town who hobnobbed with royalty, nobility, intellectuals, artists, military men, clergymen and bishops, as well as tarts, boatmen, hackney drivers and tavern keepers. He might move directly from an audience with the king at Whitehall Palace to a saucy performance by Nell Gwyn at the Duke’s theater. His diary is an intimate portrait of his age in all of its nuances.

During the 1660s, London was home for many of the ingenious “savants” and “virtuosos” who created science as we know it. New ideas were in the air, new ways of wresting knowledge from nature. The first scientific society was established—the still influential Royal Society. Robert Boyle, Robert Hooke, John Wallis and others published important experimental work that students still study today. At Cambridge, the young Newton did his brilliant work on gravity and mechanics (although the world would not know of it until a few decades later).

Pepys’ interest in science was partly intellectual curiosity and partly fashionable fad. When he acquired a “perspective glass,” an early form of binoculars, the first place he took it was to church, where from a pew in a gallery he “had the pleasure of seeing and gazing at a great many fine women.”

The decade of the diary was a cusp of history. A new age was aborning, defined by a new conviction that the world is ruled by natural laws that can be discovered by human reason. But the old ways lingered.

One moment Pepys might be observing one of the first experiments on blood transfusion, and the next he is at Charing Cross to see some perceived enemy of the realm drawn and quartered as a kind of spectator sport.

One moment he listens to Robert Hooke speculate that comets are periodic objects that obey exact mechanical laws, and the next he worries that the year 1666 is characterized by “666,” the number of the Beast of the Apocalypse.

In his diary entry for January 21, 1665, Pepys attributes his good health to the influence of his new rabbit’s foot, a lucky charm. Then he sits up late reading Hooke’s Micrographia, a book that records some of the first scientific observations with a microscope.

Among the famous illustrations in the book is that of a flea, sketched by Hooke with every bristle, crease and scale, and published in the very year that plague ravaged London, killing thousands and virtually shutting down the city. We now know that the disease is caused by flea-borne bacteria.

In other words, Pepys was thoroughly a man of his times, and his times were the Age of Science half born.

We no longer participate in public executions, carry rabbit’s feet, worry about apocalypse, fear comets, or die of the plague. Or at least most of us don’t. And the reason, of course, is reason—as embodied in the scientific way of knowing. Pepys was there at the beginning, and in his conflicted but fascinating ruminations we see how far we have come.

It is perhaps not a coincidence that science got its institutional start during the reign of the debauched Charles II. For all of his sorry human failings, the monarch encouraged religious tolerance, artistic vivacity and intellectual freedom. If history is a guide, science thrives best in societies that are secular, democratic and free.