Pluto Is Just a Baby Step for Humankind

As it advances now beyond Pluto, the New Horizons spacecraft is sending back data from its historic encounter with the dwarf planet like a long sigh of relief. It will be 16 months before scientists get the last binary bit. Trailing in its wake are broader questions about human nature and the next frontier of space exploration.

“It is, in a sense, the last first,” said the astrobiologist David Grinspoon of the Planetary Science Institute in Washington, D.C. Never again will we approach a major world in our solar system for the first time.

NASA has released the first high-resolution close-up images of Pluto. The agency's scientists say they have discovered what they believe are mountains composed of water ice on the dwarf planet. WSJ's Monika Auger reports. Photo: NASA/JHUAPL/SwRI
In interviews this week, scholars who study the origins and evolution of the cosmos—and of life within the cosmos—said that they were exhilarated as they watched the climax of a 9-year, 3-billion-mile voyage by a piano-size robot to the most distant world ever encountered by a spacecraft.

As a well-made machine, the New Horizons probe defines the technological limits of our reach, they said. As an emissary of human inquiry, it is a well-framed question that has been given a tangible form.

“Sometimes science lets us see beyond ourselves in an entirely new way,” said the evolutionary biologist Neal Shubin of the University of Chicago, who admitted that he “got pretty choked up” explaining New Horizons to his children this week.

INTERACTIVE: The Journey to Pluto
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A physicist who specializes in the abstruse field of string theory said that the mission showed how the mind could leapfrog obstacles in its way. A biologist saw in the New Horizon’s sensors a step in the evolution of our capacity to see, allowing us to peer at a world where mountains are made of ice and methane falls as snow. In the handiwork of the engineers who built and continue to manage the spacecraft, an anthropologist heard echoes of toolmakers from the dawn of human history.

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“New Horizons was a tool aptly named,” said the paleoanthropologist Tim D. White of the University of California at Berkeley, who helped to discover several species of early humans. “Broken stones were the technology that allowed our ancestors to expand from Africa. They eventually became the phones we hold and the instruments we used to envision pentaquarks, Pluto and beyond.”

For other scholars, the voyage of New Horizons advanced a narrative of exploration as old as the earliest trail of humanlike footprints, preserved in volcanic ash at Laetoli in Tanzania dating to 3.7 million years ago. “It satisfies one of the most profound and unusual qualities of our species: an unquenchable thirst to know more about ourselves—right out to the farthest reaches of the universe,” said the anthropologist Ian Tattersall of the American Museum of Natural History in New York. “This is a need that goes far, far back to the very origins of ourselves as self-conscious beings.”

A Field Guide to the Solar System
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“We are a species of explorers,” said the string theorist Brian Greene, a professor of physics and mathematics at Columbia University. “What gets us fired up are unexplored lands—sometimes literally, as when we send something to the outer solar system, and sometimes abstractly, when we explore the new lands of quantum mechanics, relativity and string theory.” He added, “When the mind soars, it goes far.”

In one way, the human mind has indeed outpaced New Horizons. When the probe left Earth in 2006, it was the fastest spacecraft ever launched. As it hibernated during its journey between worlds, astronomers using ground-based telescopes and NASA’s orbiting Kepler space telescope confirmed the existence of more than a thousand planets around other stars, with the possibility of billions more in the Milky Way galaxy.

As New Horizons made its journey, the frontier of planetary exploration abruptly expanded, said historian Roger Launius of the Smithsonian National Air and Space Museum in Washington. We have discovered that, circling other stars, there are planets hot enough to melt iron and rain lava. There is a Jupiter-size giant with the density of Styrofoam, a world of carbon that might have a core of diamond and an unknown number of planets that may closely resemble Earth.

Earlier this week, triumphant NASA officials announced that the probe’s encounter with Pluto marked the end of an era of space exploration: It completed humanity’s first full reconnaissance of the solar system.

Pluto-bound New Horizons spacecraft's Pluto Energetic Particle Spectrometer Science Investigation (PEPSSI) instrument. ENLARGE
Pluto-bound New Horizons spacecraft's Pluto Energetic Particle Spectrometer Science Investigation (PEPSSI) instrument. PHOTO: NASA
Asked if he agreed, the astrophysicist Neil deGrasse Tyson of the American Museum of Natural History bristled. “The mission, instead of completing the reconnaissance of the solar system, began the reconnaissance of a new swath of the solar system,” he said. “We’ve just begun.”

For many scientific observers, the journey of New Horizons is just a baby step for the species.

“In cosmic terms, the age of exploration has barely even begun,” said the physicist Sean Carroll of the California Institute of Technology. “Ten thousand years from now, we will look back and laugh at how impressed humans used to be at crossing an ocean, and how intimidating it seemed to cross the space between the stars.”