A senior astrophysicist and chief scientist at NASA Goddard Space Flight Center, Dr. John Mather earned the Nobel prize in physics for his work on the satellite known as COBE.

NIH may seem like its own universe, but there’s another one out there with even bigger shoulders that are getting broader every second. Scientists say that the universe is expanding, but how do they know? How do they clock it?

The NIH Director’s Cultural Lecture recently turned to NASA’s Dr. John Mather to tell the story of the big bang and the discoveries that netted him (and co-recipient George Smoot of UC-Berkeley) the 2006 Nobel Prize in physics. In the space of an hour, “From the Big Bang to the Nobel Prize and on to the James Webb Space Telescope” covered the 13.7-billion-year history of the universe and how scientists are deciphering its secrets.

“This is something very shocking,” he told a packed house in Masur Auditorium. “If you look in the mirror, you’re seeing stuff that was inside a star a few billions of years ago—your chin is made of exploded stars—and if you could grasp the significance of this, it would change your life. This is clearly something of immense cultural importance...to put the history of mankind in context.”

Photos: Michael Spencer

A senior astrophysicist at NASA Goddard Space Flight Center and chief scientist in the Science Mission Directorate at NASA headquarters, Mather earned the Nobel for his work on the satellite known as COBE—the “Cosmic Background Explorer.” Launched in 1989, COBE measured the spectrum of cosmic microwave background radiation—the residual heart of the big bang, still suffusing the cosmos.

And according to theoretical physicist Stephen Hawking, making a map and finding hot and cold spots in this radiation was “the most important discovery of the century, if not of all time.” (Mather, who has a low-key, layperson-friendly style, didn’t mention this.)

His achievement surely forms the strongest proof yet of the big bang theory. Since the discoveries of the 1920s, that theory has gone more or less like this: The universe began as an explosion of a very dense, very hot fireball, spewing matter in all directions. Space has been expanding ever since, carrying galaxies (including us) along with it. The theory explains why distant galaxies are hurtling away at such enormous speeds.

So, Mather said, rounding his index finger and thumb together, the whole presently observable universe was once compressed into something the size of a golf ball. And if you compare the primordial explosion to that of a firecracker and its debris, “you get the same math.”

Speed of expansion offers one type of supporting evidence for the big bang. The theory also predicted that scientists would one day find the background radiation (also called “the afterglow”) left over from the explosion itself.

And that’s exactly what COBE discovered: its data matched the theoretical calculations with extraordinary accuracy, the strongest proof yet that the big bang theory is correct.

“I wasn’t surprised,” Mather said.

What did surprise him was that COBE found “hot and cold spots.”

“Why are we here?” he asked. “Well, some places are denser than others, they stop expansion locally. These are primordial seeds” for galaxies, stars and planets. Other surprises: “We are a definite minority,” said Mather. That means that atoms are only 4 percent of “the stuff in the universe” which, displayed in a pie chart, seemed a mighty small sliver next to the 23 percent of “cold dark matter” and 73 percent of “dark energy.”

That “dark energy,” he explained, was discovered in 1995. “This is what we call it,” he said, “but we have no clue what it is. These are huge mysteries.”

To solve them, Mather is leading his NASA team to bring the James Webb Space Telescope to its 2013 launch. As successor to the Hubble, the Webb telescope’s mission is to see the first objects that formed after the big bang, learn how galaxies, stars and planets form and evolve and learn how planetary systems become suitable for life.

“It will go 1 million miles away into deep space,” he said, “and it should run for 5 years; we hope for 10.” For now, “We think we know how galaxies have been formed. We think we know how galaxies will grow; how stars are made inside galaxies; how planets may grow around stars.”

Yet “big open questions remain,” he said: “What happened before the big bang? What’s at its center? What are space and time? How did we get here?”

Audience members chimed in: Could there be more than just chemosynthetic life on Europa (one of the moons of Jupiter)? Possibly; astrobiology is a huge subject, Mather said. Is the universe bouncing, not just expanding? In particle physics, he noted, there are untold universes.

So are we alone?

“We can see 100 billion galaxies,” he reckoned, “each with 100 billion stars; 10²² objects could have planets. And 10 percent of stars like our sun have planets.

“In practical terms, we are alone,” said Mather. “In scientific terms, we are not.”