Photo: Levi Brown
Heidi Hammel is paid to gaze at the cosmos. As a senior research scientist for the Space Science Institute, she knows more about the outer planets of our solar system than most people know about what's in their junk drawers. Years ago Hammel led the team that was controlling the Hubble Space Telescope when a comet hit Jupiter; it was the first time astronomers watched as two solar system bodies collided. "I could see these massive dark spots that were literally the size of Earth," Hammel, 50, says, "and I thought, That's it! There's the impact."

Still, the wonder of it all didn't hit her until she stepped out for a bite to eat. "I ran into an amateur astronomer who had a small telescope set up on the sidewalk," says Hammel. "I looked through the lens at Jupiter, and"—here, she lets out a breath—"I saw the explosions. Something was happening 500 million miles away and I was staring at it on a street corner in Baltimore. I got a hitch in my chest. I was just amazed."

Actually, she was awed. Overwhelming, surprising, humbling, even a little terrifying—awe is what we feel when faced with something sublime, exceptional, or altogether beyond comprehension. And as emotions go, it's among the least understood and most difficult to study. How can science measure the feeling of peering over the Grand Canyon, or holding your newborn for the first time?

Dacher Keltner, PhD, a psychology professor at the University of California, Berkeley, devotes much of his research to studying awe. In his 2009 book, Born to Be Good, he looks at the emotions beyond the "big six" (anger, disgust, fear, happiness, sadness, and surprise), believing that more nuanced sensations—compassion, forgiveness, humility, and awe—are what push us beyond self-interest and "wire us for good." Cultivating awe, he says, is part of unlocking the truest sense of life's purpose.

Keltner grew up reading Emerson and backpacking in the Sierra Mountains—experiences that planted the seed for his later interest in studying the exalted feelings we get from nature. In his favorite experiment, he and his team had participants do a self-assessment called the 20 Statements Test, which asks subjects to complete 20 sentences beginning with "I am...," to capture the nuances of how people see themselves. One group did the test while facing a full-size replica of a Tyrannosaurus rex skeleton in the life sciences building on campus; the other completed it while facing a hallway.

The result: People who could see the awe-inducing T. rex were three times likelier to describe themselves as part of something larger ("I am an organic form," "I am part of the human species") than those who completed the questionnaire facing the hallway ("I am a soccer player," "I am a member of the Tri Delta sorority"). In Keltner's words, awe shifts a person's thinking "toward the collective."

"With awe, it's not, 'Wow, that's a really tall dinosaur,'" he says. "It's, 'Wow, there's something bigger than me.'" And the feeling can become a spur to action; Keltner cites the example of John Muir, the naturalist whose transcendent experiences in the outdoors inspired him to create the Sierra Club.

Researcher Jonathan Haidt, PhD, an associate professor of psychology at the University of Virginia, says that awe can also be prompted by witnessing acts of great generosity or humanity (à la Extreme Makeover: Home Edition). This "moral elevation," as Haidt calls it, appears to trigger the release of the bonding hormone oxytocin. "In these cases, awe sends the signal to move closer, and that clears the way for altruism, generosity, and acts of kindness," he says.

At the Berkeley Social Interaction Laboratory, Keltner and his team are attempting to figure out where awe originates in the brain. Along with neuroscientist Emiliana Simon-Thomas, he's used striking images to elicit awe in subjects whose brains were monitored by an fMRI scanner. Their preliminary findings suggest that while other pleasures—a monetary reward, a slice of cake—engage areas of the brain associated with self-interest, awe lights up the region that becomes active when we are touched, or when a mother sees pictures of her baby. Unlike the "me, me, me" response that most types of pleasure trigger, awe—and its associated increase in oxytocin—makes us feel warm and fuzzy toward others.