The U.S. government has effectively ended its search for alien life after it slashed the budget of its only center that looks for intelligent life in the universe beyond Earth.

Seth Shostak, senior astronomer for the group that runs the Search for Extraterrestrial Intelligence (SETI) Institute, headquartered in Mountainview, in northern California facility, the world's only radio telescope array specially designed to detect potential signals from distant worlds was shut down in April due to government spending cutbacks.

The money has ran out.

"It's a frustrating thing to know that there are worlds out there that may have life, intelligent life, and not be able to look for them," Shostak told Reuters.

The shutdown was specifically heart breaking for astronomers in the facility because of recent discoveries made by NASA's Kepler space telescope orbiting distant stars in the Milky Way galaxy which identifies dozens of potentially life-supporting planets.

Instead of focusing on new research targets, the astronomers are now left without a center.

According to Shostak, the Kepler telescope has detected at least 50 planets beyond the solar system in the Milky Way which could support life. With this data, scientists have theorized that there were at least 500 million potentially habitable planets out there in the galaxy.

The Allen Telescope Array, named for its chief benefactor Microsoft Corp co-founder Paul Allen, comprised of 42 dish-like antennas about 20 feet (6 meters) in diameter, and operates as a large radio telescope found in the Cascade Mountains east of Reading, California.