Oldest Light in the Universe

The European Space Agency’s Planck space telescope has obtained the most accurate and detailed map ever made of the oldest light in the universe, just 370,000 years after the Big Bang! The map suggests that the universe is expanding more slowly than scientists thought and is 13.8 billion years old—100 million years older than previous estimates. The data also show that there is less dark energy and more matter in the universe than was previously known. The resulting map, which is based on the mission's first 15.5 months of all-sky observations, reveals tiny temperature fluctuations in the cosmic microwave background (CMB). The CMB is remarkably uniform over the entire sky, but tiny variations reveal the imprints of sound waves triggered by quantum fluctuations in the universe just moments after it was born. These imprints, appearing as orange or blue splotches in the Planck map, are the seeds from which matter grew, forming stars, then galaxies, and then clusters of galaxies. NASA contributed mission-enabling technology for both of Planck's science instruments; U.S., European, and Canadian scientists work together to analyze data from Planck.