NASA's twin Mars rovers have begun their fifth year of exploration on the distant planet, far surpassing an initial goal of operating for at least three months. Scientists had thought accumulations of dust on the electricity-generating solar panels of Spirit and Opportunity would end their missions, but winds have served to occasionally clean the panels. The rovers have sent a quarter million images back to Earth, roamed 13 miles, and uncovered evidence that Mars is wetter and warmer than expected.
Colorado's vacant US Senate seat will be filled by Denver schools Superintendent Michael Bennet, Gov. Bill Ritter (D) said in announcing his surprise choice Saturday. Bennet has never held elective office, but Ritter said he has "an impressive record of bringing people together to find common ground and common-sense solutions." Bennet will replace Ken Salazar, who is slated to become Interior secretary in the Obama administration.
Alaska celebrated its 50th anniversary of statehood Saturday. The 49th state, which retains a reputation as the country's last frontier, has become a key domestic energy provider, a place for critically located military bases, and a major tourist destination.