SPACE.com -- MAP Mission: Hunting for the Big Bang's Fossils in the Sky

A view of the sky as it would have been seen by the microwave receiver of Penzias and Wilson, if it had surveyed the whole sky in 1965.The receiver was not sensitive enough to detect temperature variations in the Cosmic Background Radiation.

This all-sky image was produced in 1992 by the Cosmic Background Explorer (COBE) satellite. It was able to detect temperature variation, but at much lower resolution than MAP: the red bands are 0.0002 degrees warmer than the black regions. The red horizontal band is microwave emission from the Milky Way galaxy, not Cosmic Background Radiation.

NASA scientists expect a map like this from the Microwave Anisotropy Probe (MAP), which began charting the Cosmic Microwave Background this month in the highest resolution yet. Variations in the CMB will help resolve how much dark matter is in the universe. Red represents microwave emissions from our Milky Way Galaxy, not the CMB. Click to enlarge.

The MAP trajectory will have 3 or 5 lunar phasing loops, and a lunar gravity assist to Lagrange Point 2. The cruise time to L2 is approximately 100 days. At L2, MAP will spin like a top, with its two telescopes pointed away from the Sun and Earth. Click to enlarge.

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	MAP Mission: Hunting for the Big Bang's Fossils in the Sky By Heather Sparks Staff Writer posted: 07:00 am ET 26 June 2001

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The sky is many things to many people, but with the help of a new microwave-seeking telescope, the sky will look like a 14 billion-year-old fossil.

What's up at L2?

MAP eventually will orbit at L2, a LaGrangian gravitational balance point between the Sun and Earth. Click here for a Flash animation illustrating the LaGrange points.

Microwave radiation is all that's left of the light and heat from the Big Bang. As the theory goes, the Big Bang was an instantaneous release of all that would form the universe from a single dense speck in the void. One of the predictions for the theory is that this nuclear explosion was so intense that its radiation still bathes the universe today -- in the form of microwaves.

A new mission set to launch on June 30and called the Microwave Anisotropy Project (MAP) will allow scientists to see this radiation in the finest detail yet. Some scientists liken the prospect to unearthing dinosaur bones for the first time. This artifact radiation will tell us something of the origin, shape and fate of the universe much like the bones of prehistoric life.

"We'll be seeing the surface of the earliest universe, or 400,000 years after the Big Bang," said Charles Bennett, the project's principal investigator.

Successor to COBE

This won't be the first time the microwaves are seen, but it will be the most detailed picture of them yet. Back in 1965, two researchers, Arno Penzias and Robert Weilson at Bell Labs in New Jersey, first discovered this Cosmic Background Radiation (CBR) after building a special microwave receiver. They won a Nobel Prize for their findings, but the picture was only beginning to be filled in.

The radiation in 1965 appeared to be uniform across the sky, but in 1992 the Cosmic Background Explorer (COBE) mission, with much higher resolution than the radio receiver, detected fluctuations in the energy of the CBR. Each pixel of COBE's picture represented seven degrees of the sky, or 14 times the size of the moon as viewed from Earth. MAP will be improving that resolution 1,000-fold.

Taking the sky's temperature

MAP, a joint project of NASA's Goddard Space Flight Center and Princeton University, will accomplish this by using two telescopes facing 140 degrees away from each other to detect the tiniest temperature differences in the sky-up to a millionth of a degree. They are calibrated to detect signals specific to the CMB, blocking out microwave radiation from Earth.

"We're measuring these minute differences by putting a thermometer at every place in sky," Bennett said.

These places of temperature difference are the prize in the cosmological box of Cracker Jacks. Those specks of heat, said Bennett, are the leftover patterns of radiation that bounced off small, dense objects that existed in that ancient soup of sub-atomic particles, radiation and light of the original universe. Those teeny objects were the seeds for today's galaxies and stars, things that have never been detected before.

Finding evidence of these progenitors, Bennett said, will theoretically explain the history, content, shape and fate of the universe; questions scientists have been struggling with for years.

"We don't understand the very beginning of the universe because the laws of physics break down at those earliest times," he said. "MAP is trying to understand those very earliest times."

This will be accomplished by matching MAP's images with computer-generated scenarios that will vary the age of the universe, the rate at which it is expanding, and the amount and kind of matter in the it.

"You can put a little more exotic dark matter in and a little less ordinary matter in. It will change the fingerprint significantly," Bennett said.

Among other questions, MAP scientists plan to test the existence of exotic dark matter and dark energy, subjects that are little understood in the space science community.

"MAP will help fill in the pieces that the Big Bang doesn't tell us about," said Bennett.

The window for MAP's launch opens at 3:46 p.m. on Saturday at Cape Canaveral. Depending on the launch time, the craft will loop up to five times to a location near the Moon and back while waiting for a lunar gravity assist to shoot out 930,000 miles (1.5 million km) to LaGrange point 2 (L2) -- a gravitational balancing point between the Sun and Earth. The trip to L2 will take about three months.

Why L2 is ideal

LaGrange points are locations where the gravitational pull of two large bodies are equal to the centripetal force needed to rotate in sync with the smaller of the two bodies. There are five LaGrange points between all large masses in the universe. The points between the Sun and Earth provide ideal locations for spacecraft to orbit. The Solar and Hemispheric Observatory Satellite (SOHO) sits at L1 between the Sun and Earth with an unobscured, constant view of the Sun

L2 is an ideal location for MAP, as the distance protects the instruments from heat of Sun, and the Earth's own microwave emission and magnetic fields. It provides MAP with an unobstructed view of cold, dark space, because the Earth, Sun and Moon will always be behind it.

At L2, MAP will spin in a circular pattern much like a top. It will take six months to scan the entire sky, and will do this for two years.

Unlike other LaGrange points, L1 and L2 are slightly unstable. Every 23 days, MAP's trajectory will have to be adjusted. Still, the hold provided by this never-before-used LaGrange point will be a great way to keep the instruments as stable as possible, while it detects the oldest, weakest light in the universe.