Are we alone in the solar system? NBCNews.com Science Editor Alan Boyle (Cosmic Log) talks with JPL Chief Scientist, Mars Exploration Directorate Dave Beaty.  They continue a conversation begun March 7, 2012. Tweet questions to #askVSLinkshttp://cosmiclog.nbcnews.com/_news/2012/07/25/12952477-terrified-no-but-scientists-are-getting-nervous-about-mars-landing?litehttp://marsprogram.jpl.nasa.gov/3/7/2012 podcast: Listen at http://www.blogtalkradio.com/virtually-speaking-science/2012/03/08/dave-beaty-alan-boyle-virtually-speaking-scienceCosmicLog http://cosmiclog.msnbc.msn.com/_news/2012/03/07/10595325-how-the-hunt-for-mars-life-evolved?liteVS Science is produced in cooperation with MICA. Follow @B0yle @NASAJPL