It's impossible to gaze at the photos of Pluto sent back by the New Horizons spacecraft, and not be awash with wonder at the marvels of nature and the daring behind our choice to explore it. The surprise of worlds long dismissed as dead, dull, and very distant. The sheer audacity at sending a robot 1.4 billion miles and nearly 10 years through interplanetary space and having it hit its mark, and then mailing postcards back to prove it. The breadth and stamina of an institution, a country, and a people willing to invest so much and wait so long to hear back.

New Horizons is classic exploration, distilled to its purest essence.

Yet these are unsettled times for the larger enterprise. Since the 15th century, exploration by the West has had its ups and downs. There are eras when a small principality like Portugal might sprawl across seven seas and five continents (and maybe reached a sixth), and eras when continent-spanning surges ebb into exhaustion, and the routine of trading and cataloging.

The geopolitical rivalries that are critical catalysts change: Spain and Portugal defend, not push out. The Cold War collapses. The culture waxes and wanes, now bursting with impatient curiosity and hunger for the promises of new places; now weary, sated, and maybe cynical. Exploration needs places to visit, means to get there, reasons to go, and a moral fever to make it happen. Not all times feel that purpose with the same urgency.

Returning from the Antarctic, Apsley Cherry-Garrard described exploration as “the physical expression of the Intellectual Passion.” Exploration isn't just adventuring or trekking, nor is it solely thinking or discovering. It's the fusion of the two.

Over the centuries the character of exploration has evolved. I count three Great Ages of Discovery. The Third, today's, began in the postwar era with a renewed inquiry into Antarctica, before plunging into the deep oceans and soaring across the solar system. The linkage of ocean and space was hard welded for a while; aquanauts paired with astronauts, lunar maria and continental shelves would both be colonized, even Arthur C. Clarke wrote novels of both realms in a kind of fugue. But as the Moon race heated up, the oceans receded in popular attention and space seized the commanding heights of imagination. Hollywood filmed Clarke's 2001, not Dolphin Island.

The Third Age achieved an early climax in Voyager's Grand-Tour mission to the outer planets and beyond, launched in 1977 and now silently zooming through interstellar space. But by the time Voyager 1 reached Jupiter, the American space program was in eclipse. It had put all its eggs in a basket called the space shuttle and then the shuttle dropped. Behind the shuttle was the fantasy of colonization, particularly the ever-alluring mirage of Mars as a New New World.

Over the years the convergence of interests that propelled America's space enthusiasms has unbundled. Science, too, has diverged, many of its disciplines preferring instruments that don't need to cross the solar system. The Hubble Space Telescope was better at discovering new moons than fly-by spacecraft. Exploration can no longer rely on a soft valence with science and off-Earth settlement schemes to justify it. It has its own dynamic, and it has fallen to missions like Galileo to Jupiter, Cassini to Saturn, and New Horizons to Pluto to carry the torch of discovery.

New Horizons shows what has become possible. Each of the Voyager twins had three computers and a capacity of 16,000 words, and they recorded data on a magnetic tape; a cheap digital watch today has more high tech and as much power. Yet the massaged photos from Io, Saturn, and Triton set the gold standard for gobsmacking images of discovery. New Horizons packs more punch. Its crisp photos could have been taken over a backyard fence. They reveal not only a strange world, but a fully realized one.

New Horizons is an artifact of our age, and it speaks to what is needed to explore the yet-unvisited shorelines of space, and what such endeavors cost. Most exploration in the coming decades will focus on the deep oceans—those on Earth, not on Enceladus or Europa. Robotic expeditions to the deep are multiplying. They will be far cheaper and more productive, as generators of science, than probes through the icy crust of a Saturnian moon. If all we want is information, Earth-bound science may do, and it can come from a lab more easily than an abyssal plain, much less a planetoid 750 million miles distant.

But New Horizons, like all great exploration, does more than inform. It transmutes an inquiry into a quest. It matters not that the vehicle is a machine: We made it, which means it embodies our values and yearnings and speaks to our sense of ourselves as fully as any painting or cathedral might. We anthropomorphize the machines, as we should.

The Voyagers and New Horizons differ from past voyages of discovery. They won't come entwined with visions of New Jerusalems. They won't find alien life and so won't be burdened with what Henry Stanley called the “moral miasma” of imperialism. They won't be part of a geopolitical race to claim trade with the Oort Cloud. They won't parade technological triumphalism as a surrogate for ideological strength.

In the end expeditions like New Horizons are a cultural statement by which we remember who we are and how we came to be, and we support them for the same reasons that we sponsor museums and set aside nature preserves.

New Horizons will not revive our economy or revolutionize an understanding of our place in the Great Scheme of Things. But it is an extraordinary achievement that we ought to pause and celebrate. It reminds us, particularly in an age of selfie sticks, that there is a lot more out there than meets the eye of an iPhone, and that we are often at our best when we strive to find it.