Its multicolored ovals have become some of the most distinguishable pictures in science. Its estimate of the age of the universe is the most accurate ever produced. Its science team ought to win the Nobel Prize for Physics, Nobel predictors at Thomson Reuters say. But now, after nine years in space, the accomplished Wilkinson Microwave Anisotropy Probe (WMAP) is headed for its retirement home.
The spinning WMAP satellite scanned the sky to measure tiny variations in the temperature of the cosmic microwave background radiation 380,000 years after the Big Bang. Scientists consider the CMB the first light from the young universe after matter and light could exist independently as the universe cooled. Only sensitive microwave space telescopes can detect the temperature fluctuations, which amount to just a millionth of a degree against an average backdrop of less than -450 degrees Fahrenheit. [Spaceflight Now]
By finding these tiny differences in energy, WMAP allowed scientists to calculate when the birth of the universe happened—13.75 billion years ago, plus or minus about 0.1 billion years (100 million years or so).
But WMAP didn’t stop there. Although scientists have hypothesized that the universe went through rapid inflation just after the Big Bang, WMAP has managed to find even more supporting evidence that this growth spurt did happen. Thanks to WMAP, we also know that a mysterious entity called dark energy fills 72 percent of the cosmos and dark matter makes up for around 23 percent. “Normal” baryonic matter makes up for a piddly 4.6 percent of the observable universe. [Discovery News]
The satellite launched in 2001. Now that its nine-year mission has ended, NASA moved it from its position at the L2 Lagrange point to a permanent parking orbit. The researchers behind WMAP will continue to analyze its data for two more years—when a mission has been so fruitful, you want to stay with it until the bitter end.
Says principal investigator Charles Bennett of WMAP’s legacy:
“It was almost miraculous,” Bennett said. “All of a sudden, in one fell swoop, we suddenly had all these numbers: the density of atoms, the density of dark energy, the age of the universe, when the first stars formed, the distance light has traveled to get to us…. It was just really stunning to suddenly have all this fall into place.” [Wired.com]
Bad Astronomy: New WMAP results: quantum fluctuations, galaxies, and the first stars
Cosmic Variance: WMAP 5-Year Results Released
DISCOVER: A Field Guide to the Invisible Universe
DISCOVER: The Fingerprint of Creation (From our wayback machine, a 1992 article about WMAP’s predecessor, COBE)