into the first trillionth of a second
Courtesy Johns Hopkins University
and World Science staff
Scientists say they have new evidence for what happened during the universe’s first trillionth of a second, obtained from looking at the afterglow of the explosion that started it all.
During that period, many cosmologists believe the universe grew from submicroscopic to astronomical size in far less than an eye blink.
Researchers say the new findings are the best evidence yet for this scenario, known as “inflation.”
The evidence was gathered from what’s believed to be the afterglow of the Big Bang
explosion that gave birth to the universe, some 14 billion years ago.
This light, called the cosmic background
radiation, is thought to provide a sort of picture of the universe as it
was shortly after the Big Bang.
In 2003, researchers announced that a NASA satellite known the Wilkinson Microwave Anisotropy Probe, or WMAP, had produced a detailed
portrait of the infant universe by measuring variations in temperature of the
glow. That was believed to answer many longstanding questions about the universe’s age, composition and development.
The new project has built on those results using the satellite to measure another pattern in the afterglow. This could shed light on the universe’s first moments, which sowed the seeds for the first star formation 400 million years later.
“It amazes me that we can say anything about what transpired within the first trillionth of a second of the universe, but we can,” said Charles L. Bennett of Johns Hopkins University in Baltimore, Md., principal investigator for the project. “We have never before been able to understand the infant universe with such precision. It appears that [it] had the kind of growth spurt that would alarm any mom or dad.”
The research group, known as the WMAP team, has submitted its findings to
The Astrophysical Journal.
The satellite can resolve features in the cosmic microwave background based on
polarization, or the way light is changed by the environment through which
it passes. For example, sunlight reflecting off of a shiny object is polarized.
The researchers compared the brightness of small features to large ones,
a process analogous to comparing the heights of short-distance ripples
and long-distance waves on a lake.
One long-held prediction was the brightness would
be the same for features of all sizes. In contrast, simple versions of
the inflation theory predict small features are less bright, a trend
found in the new data.
The newly detected pattern is the weakest cosmological signal ever
“This is brand new territory,” said Lyman Page of Princeton University in Princeton, N.J., a team member.
The new findings also support established theories on what has happened to matter and energy since the inflation, the researchers said, providing a consistent picture of how the cosmos grew from microscopic fluctuations to form stars, planets and life.
According to this picture, researchers say, only 4 percent of the universe consists of ordinary atoms. Another 22 percent is an as-yet unidentified dark matter that exerts a gravitational pull but seems undetectable otherwise. And 74 percent is a mysterious dark energy, which is now causing another growth spurt—fortunately, they say, gentler than the one at the beginning.
The satellite was launched in June 2001, and is now a million miles from Earth in the direction opposite the sun.
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