Aliens abound on the movie screens, but in reality we are still trying to find out if we share our universe with other sentient creatures. SETI, the search for extraterrestrial intelligence, is our attempt to detect evidence of a distant technology, in pursuit of cosmic company. On April 13, astronomer Jill Tarter will speak on "Are We Alone?" as the 2010 Sturm Memorial Lecturer. Tarter is director of the SETI Institute's Center for SETI Research. In 2004 Time Magazine named her one of the 100 most influential people in the world, and in 2006 Tarter became a National Advisory Board member for the…