Scientific inquiry can be driven by a variety of motives. Certainly the quest to cure cancer can be a matter of wanting to simply help, but even anger, frustration, or grief can be involved. Recently, I saw a news story of a researcher who forged results for new cures, exposing patients to dangerous treatments for his own pride or vanity. And here, scientists sometimes seek recognition, or positions of power. In academia, jobs are won and lost based on the progress of scientific research. That is motivation enough for some.

But in the ideal world, scientific inquiry would be driven by just that: inquiry. We ask questions because we are curious to know the answer.

Not long ago, there was a count-down, accurate supposedly to the second, to the landing of Curiosity on Mars. The name, suggested by a sixth grader as part of the “Name NASA’s Next Mars Rover” contest, is apt. Even before it reached the red planet, the rover was gathering data to help scientists learn about the tribulations faced by physical objects in outer space. Curiosity was equipped to detect solar radiation, to give details about how well (or not) the walls of the space capsule protect from cosmic radiation that would be potentially damaging to humans. I imagine how its sensors must have struggled as solar radiation went berserk in the last few weeks of its flight. The rover, now landed, is an unmanned laboratory trying to learn whether the planet’s surface could support life, or if it has. We have nearly succeeded in making a car curious about the existence of life on another planet.

And after this landing? I don’t know. The public’s attention has turned, once again, to its old curiosity about what lies beyond the solar system, and Voyager 1 has finally, after 36 years, reached that enigmatic threshold where the sun’s influence has faded. And now we are all the more curious, now that the answer seems somehow closer to our grasp. We are all the more curious about what lies beyond our immediate reality; and the physical beyond that we have so far only accessed, via what that outside sends to us through photons and neutrinos and other waves and particles.

Yet, in the case of space exploration, the motive for science was, in the most realistic terms, war. It was a matter of vanity on an international scale. But curiosity, long before human beings set foot on the moon, long before NASA was developed, had people wondering what the moon is made of, how far away it is, whether anything could live there, and much more. I recently read H.G. Wells’s First Man in the Moon, and I was blown away by his satirical solution to the unanswerable. And as for Mars, its periodic retrograde motion was one of the great quandaries when philosophers were trying to model the solar system. Speculation about life on the red planet has frequently run rampant. When we cannot know the answer, it seems that we try very hard to make one up.

People have lived their lives on that curiosity, eating and breathing it. Certainly there has been prestige and recognition for some scientists who have sought answers in space, but Copernicus and Galileo also found persecution when they pursued science. What can be strong enough to warrant house arrest? What can be the purpose of billions of dollars, only to burn up in Venus’s atmosphere? If not curing cancer or defeating the Soviets? Curiosity.

On a physiological level, individuals may be curious because they seek the reward of learning. Certainly that’s what drives learning in young children. Areas of the brain experience the sensation of being rewarded when curiosity leads to new information. The rush of a new discovery is substantial, proportionate perhaps to how curious you were to begin with. If you spend a long time seeking an answer, if you allow curiosity to carry you into your imagination, if you struggle and devote yourself completely to finding an answer, then the brain’s delight must be overwhelming. Think of a child who is rewarded by finally mastering the tying of her shoes, her cries of delight and pride, of success and discovery. How many times should I multiply that for setting foot on the moon? Mars? Reaching beyond the sun’s all-powerful gravity?