This light lost energy as the universe expanded over 13.7 billion years, so WMAP now sees the light as microwaves. By making accurate measurements of microwave patterns, WMAP has answered many longstanding questions about the universe's age, composition and development.
The three major findings that WMAP made are: new evidence that a sea of cosmic neutrinos permeates the universe, clear evidence that the first stars took more than a half-billion years to create a cosmic fog, and, tight new constraints on the burst of expansion in the universe's first trillionth of a second.
According to Gary Hinshaw of NASA's Goddard Space Flight Center in Greenbelt, Maryland, "Ours is the first generation in human history to make such detailed and far-reaching measurements of our universe."
As for the first finding, WMAP has determined that the universe is submerged in a sea of undetectable particles called neutrinos, left over from the first few seconds of the big bang.
In theory, they should still be buzzing around, a soup of slippery particles that by today has been chilled to a temperature of only 1.9, a Celsius above absolute zero.
Another breakthrough derived from WMAP data is clear evidence the first stars took more than a half-billion years to create a cosmic fog.
The data provide crucial new insights into the end of the "dark ages," when the first generation of stars began to shine. The glow from these stars created a thin fog of electrons in the surrounding gas that scatters microwaves.
"We now have evidence that the creation of this fog was a drawn-out process, starting when the universe was about 400 million years old and lasting for half a billion years," said WMAP team member Joanna Dunkley.
A third major finding arising from the new WMAP data places tight constraints on the astonishing burst of growth in the first trillionth of a second of the universe, called "inflation", when ripples in the very fabric of space may have been created.
"The new WMAP data rule out many mainstream ideas that seek to describe the growth burst in the early universe," said WMAP principal investigator, Charles Bennett, of The Johns Hopkins University in Baltimore, Maryland.
"It is astonishing that bold predictions of events in the first moments of the universe now can be confronted with solid measurements," he added.