For an astronomer, Adam Riess would make a pretty lame tour guide to the night sky.
He didn't grow up glued to a backyard telescope. He rarely gives the stars a second look after dark. And he's more likely to spot a Ford Taurus on the street than its namesake in the heavens.
"I can find the Big Dipper. I can find Orion," he says, ticking off the stellar geography he knows. "After that, I would be struggling."
But for answers to the big questions - What's the universe made of? How will it end? - this rising young star of astronomy is the guy to see.
Many scientists spend a lifetime quietly probing the cosmos without making a dent. Riess, a 31-year-old astrophysicist at the Space Telescope Science Institute in Baltimore, has made a discovery so profound it upends nearly 70 years of thinking on how the universe ticks.
It sounds like something straight out of "Star Trek": a mysterious invisible force out-muscles gravity, propelling galaxies and other matter outward at an accelerating clip. Baffled scientists dub it "dark energy."
Yet last month, three years after he and others first discovered hints of it, Riess delivered the strongest evidence yet that dark energy is no science fiction.
The findings have sent theoretical physicists into a tizzy and spawned an inflating universe of books and TV documentaries probing its implications. "If it's true," says Alex Filippenko, an astronomer at the University of California at Berkeley, "it's one of the major discoveries of the century."
That a discovery this significant could be made by a scientist who is more comfortable with computers than his constellations shows how astronomy and its practitioners are changing.
Until not too long ago professional stargazing was a tough business, demanding as much physical stamina as scientific know-how. Curled up inside their frosty mountain-top telescopes, astronomers pulled all-nighters photographing the heavens, struggling to suppress the slightest shiver lest it throw off their sensitive instruments.
Later, eyeballing these hard-won snapshots, astronomers struggled to achieve even basic insights: how swirly galaxies looked, for example.
But computers are changing all that. Much as they have revolutionized fields from biology to meteorology, digital technology is making astronomy much less physical and far more precise.
"People don't realize what a high-tech endeavor astronomy is today," says Don Figer, an astronomer at the Space Telescope Science Institute.
At the prestigious Keck Observatory in Mauna Kea, Hawaii, for example, astronomers gaze at the stars on TV screens, in an air-conditioned control room 13,000 feet below the frigid peak.
Astronomers have also abandoned old-fashioned film. Now photons of light dribbling in from the heavens are captured by light-sensitive silicon chips, which have vastly improved how much detail astronomers extract from the sky.
That's where people like Riess come in. He is among the growing number of scientists attracted to what some consider the dirty side of astronomy: mining the growing avalanche of digital data for heavenly secrets.
"I think that's where the next generation of discoveries will come from," Riess says.
He probes the cosmos in a cluttered office with a leafy view of the Johns Hopkins University campus, surrounded by blow-ups of exploding stars (his specialty), tomes on astrostatistics and a whiteboard awash with Ph.D.-level graffiti.
Since he rarely treks to telescopes himself, the photos on his wall are usually as close as he gets to his research subjects. His discoveries, he says, have hinged on his PC and lots of "high-powered" math and statistics.
As far back as he can remember, Riess says, he has been drawn to puzzles and finding out why things are the way they are. As a kid growing up in Warren, N.J., for example, he noticed that people often pass by pennies left on the ground.
Seeding his high school with pennies, nickels, dimes and quarters, he decided to find out how much change it would take to entice someone to pick it up. (His conclusion: His classmates were far too well off, because a teacher was the first to pocket a quarter.)
Chatty and quick with a joke, Riess comes across more like a salesman than a stereotypical science nerd.
He works hard to paint himself as a normal guy who's into pro football, knocking back a few beers, collecting rare coins. Almost as an afterthought, he'll mention that he just happened to study physics at MIT, get his doctorate in astrophysics at Harvard - and, oh yeah, finished his doctorate in four years instead of the typical six.
It was his fascination with puzzles - and a dash of luck - that helped Riess nail one of astronomy's deepest mysteries: How will the universe end?
At the start of the 20th century, most astronomers thought the universe was static, its heavenly bodies like a mobile in a child's bedroom.