When it comes to inflation, cosmologists are pondering a future that
probably would leave even Alan Greenspan scratching his head. Of course, the
Federal Reserve chairman is merely concerned with economic policy and hasn’t
had to stare down the complexities of how the universe pumped up after the
Big Bang.

And now, new research tools promise tantalizing glimpses of characteristics
in the universe that until now have gone unseen.

“We might, in a technical sense, soon observe the beginning of time,”
University of Washington cosmologist Craig Hogan writes in the March 22
edition of the journal Science.

It was just a decade ago that a National Aeronautics and Space
Administration project called the Cosmic Background Explorer, or COBE, began
returning data aimed at mapping the universe’s background radiation, which
was first observed in 1965. That radiation is residual heat from the Big
Bang, the event that sparked the beginning of the universe some 13 billion
years ago.

COBE produced a map that included ripples, or amplitude fluctuations, >1he
structure of space-time across billions of light years. Those ripples are
the largest structures humans ever will be able to see, Hogan said. But they
also are greatly magnified images of the smallest structures ever visible –
the same fluctuations that started out smaller than a subatomic particle at
the Big Bang, then were frozen into the fabric of space-time and stretched
as inflation expanded the universe to its current size.

Upcoming projects promise even more-detailed information, said Hogan, a UW
physics and astronomy professor.

In a Perspective article for Science, he discusses the possibility that new
experiments will shed clues about subatomic particles called gravitons and
perhaps bring enough information to unite quantum mechanics and relativity,
the two great theories rooted in the work of Albert Einstein. These new
experiments include a NASA mission called Microwave Anisotropy Probe, or
MAP, that was launched last year with a mission to collect information to
chart the microwave light left over from the Big Bang.

Unlike subatomic particles that make up matter and energy as we know them,
gravitons are elementary particles that compose the fabric of space and

“No one has ever seen a graviton, but with these new efforts we might,”
Hogan said. “If you can see gravitons in these maps, then you’ll start to
see the essence of space and time and matter.”

Hogan also believes the next generation of research might shed light on
other cosmological puzzles. One of these involves the holographic principle,
which states that everything that happens three-dimensionally can actually
be specified by the amount of information it would take to project it
two-dimensionally, like a hologram. If that turns out to be true, Hogan
speculates that all the information needed to show the entire universe
during early inflation, shortly after the Big Bang, could have fit on a
compact disc.

Whatever is learned from the new research, Hogan said, will lend to the
basic scientific understanding of time, space, matter and energy. And while
that might sound terribly esoteric, he said, it could turn out to have very
practical applications.

He noted that Einstein’s theory of space-time and gravity, called general
relativity, was long regarded as something of an elegant ornament for the
science of physics, but nothing with any realistic usefulness. However, it
turns out there are practical applications. For instance, without
relativity, backcountry hikers, drivers and pilots – let alone smart bombs –
couldn’t use global positioning technology.

“If you want to hit a cave in Afghanistan, you need general relativity,”
Hogan said. “And why is that? It’s all based on light traveling through
space, and precisely timing the pulses of light.”


For more information, contact Hogan at (206) 616-4475 or