Just how sure are they that we are not alone in the universe?
The possibility of extraterrestrial microbial life is "close to 100 percent," Dan Werthimer, director of the SETI [search for extraterrestrial intelligence] Research Center at the University of California, Berkeley, told a House panel this week.
"It would be bizarre if we are alone," he said.
Seth Shostak, a senior astronomer at SETI, told Congress that we will probably find life on other planets and soon.
"The chances of finding it I think are good and if that happens it will happen in the next 20 years depending on the financing," Shostak said.