"I don't think it would be any wonder if life like us exists somewhere else as space is vast," said Mitsumi Fujishita, radioastronomy professor at Kyushu Tokai University, who heads the research.

The five-day search is being done jointly at the Nishi-Harima Astronomical Observatory, run by western Hyogo prefecture which includes the city of Kobe, and the state-run Mizusawa Astrogeodynamics Observatory in northern Japan.

There have been earlier Japanese efforts to detect signs of aliens but this is the first such search involving a state-run organization, according to researchers.

The Mizusawa observatory using a radio telescope with a diameter of 10 meters (33 feet) is trying to find radio waves while the Nishi-Harima observatory, with a two-meter reflector telescope, aims to detect light.

They will focus on the area near the Hydra constellation where a US researcher detected radio waves in 1988.

Another researcher said it "will be very difficult to find signs as we don't know which radio waves would come at what time or from where."

"Even if they cannot detect anything, however, it is important to find out what it (the lack of detection) means scientifically," he said.

Japan is drafting an ambitious space program, with a goal of a manned station on the moon by 2025, after successfully sending into space a satellite last Saturday 15 months after a similar unmanned launch failed disastrously.

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