"A more recent CMB experiment, the Wilkinson Microwave
Anisotropy Probe (WMAP), was launched in 2001 to map
the CMB more precisely. It's a little over halfway
finished with its four-year mission. WMAP can detect
temperature differences of a millionth of a degree.
The WMAP results have been used to find the age of the
universe (13.7 billion years) and the time when the
first stars formed (200 million years after the Big
Bang), much earlier than scientists thought. WMAP also
found that the rate of expansion of the universe, in
case anyone is interested, is 71 kilometers per second
per megaparsec. Because the WMAP measures the
non-uniformity details of the universe very well, the
data have also been used recently to see if the
universe is finite but "wrapped." A "wrapped" universe
is one that is constructed like a video game: it looks
infinite, but when you move off the edge of the left
side, you reappear on the right side. (You've probably
seen Star Trek episodes like this.) If the universe
were "wrapped" then you would see the same temperature
patterns in two different places in the universe,
indicating they are actually the same place. So far no
evidence has been found that the universe is
"wrapped." You definitely want to keep your eyes open
for more wonderful results from WMAP in the next few years."
The straight dope