What is our universe made of? To help find out, ESA launched the
Planck satellite to map, in unprecedented detail, slight temperature differences on the oldest surface known -- the background sky left billions of years ago when our universe first
became transparent to light. Visible in all directions, this
cosmic microwave background is a complex tapestry that could only show the
hot and cold patterns observed were the universe to be composed of specific
types of energy that evolved in specific ways.
The results,
reported last week, confirm again that most of our universe is mostly composed of mysterious and unfamiliar
dark energy, and that even most of the remaining matter energy is strangely dark. Additionally, Planck data
impressively peg the age of the universe at about 13.81 billion years, slightly older than that
estimated by various other means including NASA's
WMAP satellite, and the
expansion rate at 67.3 (+/- 1.2) km/sec/Mpc, slightly lower than previous estimates.
Some features of the
above sky map remain unknown, such as why the temperature fluctuations seem to be
slightly greater on one half of the sky than the other.