China's Five-hundred-meter Aperture Spherical Radio Telescope (FAST), the world's largest filled-aperture and most sensitive radio telescope, has officially opened to the world starting Wednesday.

Experts expect the gigantic telescope to bolster global astronomical research and find answers to some of the biggest unknowns in modern astrophysics and cosmology.

Astronomers globally can submit their observation applications for evaluation till May 15 and the results will be announced on July 20, according to a statement by the National Astronomical Observatories (NAO) under the Chinese Academy of Sciences (CAS). Observations by overseas scientists will begin in August.

About 10 percent of FAST's observation time in the first year, roughly 450 hours, is expected to be allocated to foreign scientists, said Li Di, chief scientist of the telescope and a researcher with the NAO.

Many global astronomers have been looking forward to the opening of FAST following the collapse of the 305-meter vast telescope at Arecibo Observatory in Puerto Rico last December. The competition for grabbing observation time is set to be fierce, Li said.