John Allen Muhammad's life came to a close Tuesday night as the convicted D.C. sniper was put to death by lethal injection at a prison in southern Virginia. According to prison spokesman Larry Traylor, officials declared Muhammad dead at precisely 9:11 p.m. at the Greensville Correctional Center.

President Barack Obama tells an audience of thousands at Fort Hood that the 13 men and women who died there on Nov. 5 must never be forgotten. "Their lives speak to the dignity, the strength, the decency of those who serve," Obama says. After his address, the president and first lady plan to visit a nearby military hospital to meet with survivors of the attack.

Researchers are ranking the 50 U.S. states according to which have the happiest residents. In general, they say, the states with wealthier, better educated and more tolerant residents are the happiest. Well-being is highest in the Mountain and West Coast states, followed by the Eastern Seaboard.

The Vatican considers the possibility of extraterrestrial life -- and ponders the implications for the Catholic Church. Scientists from the Vatican Observatory recently hosted a five-day conference of astronomers, physicists and biologists to explore the issue. Said one Jesuit priest: "How can we rule out that life may have developed elsewhere?"

A new study by Consumer Reports finds what it deems unhealthy levels of bisphenol A, or BPA, in a variety of canned foods. Although this preservative has been linked to diseases in animals, industry groups insist it is safe. Two recent measures in Congress are calling for a ban on BPA, and both the FDA and EPA plan to study the issue in coming months.

The toast of the auction circuit this week is a bottle of beer recovered from the famous Hindenburg crash in New Jersey more than 70 years ago. The modest drink, which still bears a Lowenbrau label, is expected to become the most expensive beer ever sold, the auction house says.

NASA marks the 400th anniversary of the telescope by releasing one of the most detailed images to date of the heart of the Milky Way. The image, a composite created by the Hubble and Spitzer space telescopes and the Chandra X-ray Observatory, will go on display at scores of planetariums, libraries and schools.