The online 'computational knowledge engine' calculates answers, unlike Google, which searches for information that already exists.How long does it take to get to Saturn at, say, the speed of light? With Wolfram Alpha, the online "computational knowledge engine" that launched Monday, the answer -- 75 minutes -- can be found in a fraction of a second. Web users can submit customized questions to the service, and Wolfram Alpha will try to work out the answer on the fly. The chance that a healthy 35-year-old woman will contract heart disease in the next 10 years? One in 167. The temperature in...