. >> well, don salo said i aged 40 years in four.ted in partying. >> do you still smoke weed? >> actually, no. >> why not? >> after being in prison and seeing how drugs destroyed the lives of so many people around me, i can't get near it. >> earlier that year was that interview. so the new evidence, the new dna evidence in the knox case is expected to be revealed in court in italy this week. >>> all right, coming up, next, the science behind -- >> hi, i'm commander chris hatfield. the first canadian to walk in space and i watched "the science behind" on cnn. >>> in the next hour, the president's health care law takes another hit. find out why at the top of the hour. >>> this week on "the science behind," we take a look at chris hatfield's journey in space. he spent 144 days as the commander of the international space station. that's where he learn arned the nickname "the singing astronaut requests from this per formansz from space. >>. ♪ this is ground control to major tom ♪ ♪ you've really made the grade ♪ and the papers want to kno