One of the world's biggest radio telescopes collapsed in what an astronomer lamented as a "major blow" to science.

The 26-year-old instrument, a dish the length of a football field in diameter, gave way late Tuesday, said George Seielstad, assistant director for Green Bank operations at the National Radio Astronomy Observatory."Absolutely nobody was hurt, but the telescope itself is beyond repair, and there was damage to the control room where the telescope is operated from," Seielstad said Wednesday.

The cause of the collapse was under investigation. "We know it was not weather-related because last night was a beautiful evening," Seielstad said.

The 300-foot telescope, which resembles a TV satellite dish, was used to pick up naturally emitted radio signals from space from distances as great as 10 billion light years.

The telescope was completed in 1962 at a cost of $850,000 and took 18 months to build, he said.