Gary Zank, (second from right) Department of Space Sciences, Center for Space Plasma and Aeronomics Research (CSPAR), University of Alabama in Huntsville, speaks at a news conference on NASA's Voyager 1 spacecraft, Thursday, Sept. 12, 2013 at NASA Headquarters in Washington. NASA's Voyager 1 spacecraft officially is the first human-made object to venture into interstellar space. The 36-year-old probe is about 12 billion miles (19 billion kilometers) from our sun. New and unexpected data indicate Voyager 1 has been traveling for about one year through plasma, or ionized gas, present in the space between stars. A report on the analysis of this new data is published in Thursday's edition of the journal Science.