A new mission set to launch on June 30 and 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
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.
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