A quest for far-out mileposts in space

AUSTIN, TEXAS — In the vastness of space, how far is far?

That question has simmered in G. Fritz Benedict's mind since he was 8, when a family friend took him into the backyard of his home and pointed to the constellation Orion.

"Something in my brain went 'snap,' " said Benedict, an astronomer at the University of Texas at Austin.

The experience set him on a lifelong quest to answer one of the most arcane questions in astronomy: How exactly do you measure the universe?

Astronomers have wrestled with the issue for millenniums, and for most of that time they haven't even come close.

Their calculations have been painstakingly constructed into a framework known as the cosmic distance ladder.

Each rung is made up of a stellar object whose distance is roughly known and can be used to measure the distance of neighboring objects.

The problem is that over cosmic distances, minuscule inaccuracies can compound into huge miscalculations.

"People say, 'What's the big deal?' " said Benedict, a youthful man of 62 with a quick smile and an inexhaustibly detailed mind. "I tell them, 'What if I handed you a yardstick and told you, 'I don't know if it's 32 or 42 inches long?' "

Caltech astronomer Shri Kulkarni is more blunt. "Astrometry is the fundamental basis of astronomy," he said. "It's the way you know such things as the size of the universe. Other than that, you know nothing."

Benedict's quest has taken him on a lonely 30-year journey filled with bureaucratic roadblocks and technical delays that made him doubt whether he would ever get the chance to make his measurements.

While most of his peers went to work on the big questions of the universe -- uniting gravity and quantum mechanics, searching for extraterrestrial life or figuring out how the universe will end -- Benedict has obsessed over one set of measurements: the distance to a type of star known as a Cepheid.

There's been little glory. And even as the tools of cosmic surveying are reaching once-unimaginable accuracy, American astrometry is fading as students move into sexier topics.

"There's a rather gloomy future," lamented retired Yale University astronomer William F. van Altena, the most illustrious astrometrist of his era. "This is really a sad state of affairs."

Early efforts stumbled

Surveying the universe is mostly an exercise in being wildly wrong.