However, getting enough funding to keep scanning the skies is a constant problem. For example, the Allen Telescope Array in northern California — which the SETI Institute uses — was designed to consist of 350 radio dishes, but just 42 have been built to date. And the array had to go into hibernation in April 2011 due to budget shortfalls. (It came back online in December of that year after more funding was found.)

The funding situation colors any discussion of SETI activities and timelines, Shostak said.

The 24-year estimate, for example, “depends on continued SETI funding, which is in dire straits right now,” he told Space.com after his talk at the NIAC symposium.