Is Earth the only planet with life?

It’s one of many tantalizing scientific questions that NASA is failing to adequately address, several experts said in response to the 16.8-billion-dollar 2007 budget that President George W. Bush’s proposed for the U.S. space agency on Monday.

The spending plan, which is a 3.2 percent increase over 2006, places priority on the space shuttle’s return to flight, space station construction, and development of the next-generation spacecraft to ferry humans to the moon and, eventually, Mars.