The Microwave Anisotropy Probe (MAP), scheduled for
launch June 30, will journey into deep space on a voyage to
explore some of the deepest mysteries of the cosmos.
Scientists hope to determine the content, shape, history, and
the ultimate fate of the universe, by constructing a full-sky
picture of the oldest light. MAP is designed to capture the
afterglow of the Big Bang, which comes to us from a time well
before there were any stars, galaxies or quasars. Patterns
imprinted within this afterglow carry with them the answers
to mysteries such as: What happened during the first instant
after the Big Bang? How did the Universe evolve into the
complex patterns of galaxies that we see today? Will the
Universe expand forever or will it collapse?
To answer these questions, MAP’s measured pattern of the Big
Bang’s afterglow, like a fingerprint, will be compared
against the unique fingerprint pattern predicted by each
cosmic scenario to find the right match. “We are tremendously
excited about this mission because it will help answer basic
questions that people have been asking for ages,” said Dr.
Charles L. Bennett, Principal Investigator for the MAP
mission at NASA’s Goddard Space Flight Center, Greenbelt, MD.
“MAP’s unprecedented accuracy and precision will allow us to
determine the nature and destiny of the universe.”
According to the Big Bang theory, the universe began about 14
billion years ago as an unimaginably hot and dense fog of
light and exotic particles. The Universe has since
continuously expanded and cooled. The whole Universe is
bathed in the afterglow light from the Big Bang. The light
that is now reaching us has been traveling for about 14
billion years, thus allowing us a look back through time to
see the early Universe.
“The cosmic microwave light is a fossil,” says Professor
David T. Wilkinson, Princeton University, Princeton, NJ.
“Just as we can study dinosaur bones and reconstruct their
lives of millions of years ago, we can probe this ancient
light and reconstruct the Universe as it was about 14 billion
years ago.”
MAP views the infant universe by measuring the tiny
temperature differences within the extraordinarily evenly
dispersed microwave light, which now averages a frigid 2.73
degrees above absolute zero temperature. MAP will resolve the
slight temperature fluctuations, which vary by only
millionths of a degree. These temperature differences point
back to density differences in the young Universe, where
denser regions gave way to the vast web-like structure of
galaxies that we see today.
A great deal of effort over the past 35 years has gone into
measurements of the afterglow light from the Big Bang. In
1992, NASA’s Cosmic Background Explorer satellite discovered
tiny patterns, or “anisotropy,” in its full-sky picture of
the light. Balloon-borne and ground-based experiments have
further advanced our knowledge. The upcoming MAP full-sky
picture, to be made with unprecedented accuracy and
precision, will dramatically revolutionize our view of the
Universe.
MAP required an extraordinary design to achieve its accurate
and precise measurement capability. “Nothing has ever been
built like it before,” said Dr. Edward Wollack, a science
team member at Goddard. “To measure the cosmic glow reliably
to a part in a million, to millionths of a degree has been
the grand challenge. That’s like measuring the weight of a
cup of sand down to the resolution of a single grain.”
About a month after its launch on a Delta II rocket from Cape
Canaveral, FL, MAP will swing past the Moon, boosting its
orbit to the second Lagrange Point, or L2. This is the first
time a spacecraft will be in orbit around the L2 point. The
Italian-French mathematician Josef Lagrange discovered five
special points in the vicinity of two orbiting masses where a
third, smaller mass can orbit at a fixed distance from the
larger masses. L2 is four times further than the Moon in the
direction away from the Sun and requires very little fuel to
maintain orbit.
After a three month journey, MAP will begin to chart the
faint microwave glow from the Big Bang. It will take about 18
months to build up a full-sky picture and perform the
analysis. The MAP hardware and software were produced by
Goddard and Princeton. Science team members are also located
at the University of Chicago, IL; the University of
California, Los Angeles; Brown University, Providence, RI;
and the University of British Columbia, Vancouver. MAP, an
Explorer mission, cost about $145 million. More information
is available on the Internet at:
http://www.gsfc.nasa.gov/gsfc/spacesci/map/map.htm
