Why is the temperature of the universe 2.726 Kelvin?

The Cosmic Background Explorer satellite has recently made the most accurate measurement of the temperature of the universe, determining it to be 2.726 +/- 0.01 kelvin. In trying to understand why the temperature has this value, one is led to discover the most fundamental features of the universe-an early, radiation-dominated epoch, enormous entropy per nucleon, synthesis of the light elements around 3 minutes after the bang, and a small excess of matter over antimatter-as well as some of the most pressing issues in cosmology today-the development of structure in the universe and the identification of the nature of the ubiquitous dark matter.     

How long is the day on Saturn?

Determining a planet's rotation period can be difficult if the planet lacks a solid surface. However, for planets with an internal magnetic field, emissions at radio wavelengths are modulated by the planet's rotation rate. The latest results from the Cassini spacecraft seem to indicate that Saturn's rotation rate has slowed down by 6 minutes since the Voyager 1 and 2 spacecraft flew by the planet in 1980 and 1981, but it is unclear whether a slowdown has in fact occurred. Future data collected by Cassini may be able to resolve the question.