The world's largest radio telescope has begun searching for signs of extra-terrestrial life in outer space.

The £138m dish, which began operating on Sunday, measures 500 metres in diameter and took five years to construct in China's Guizhou region.

As well as searching for signs of intelligent life outside the galaxy, the dish will observe distant pulsars - tiny, rapidly spinning neutron stars believed to be the products of supernova explosions.

Hundreds of astronomers and enthusiasts watched the launch of the Five-Hundred-Metre Aperture Spherical Telescope (FAST), China's state news agency Xinhua reported.

Image: The telescope pictured during construction in November 2015

In a test run before the launch, FAST detected electromagnetic waves emitted by a pulsar more than 1,300 light-years away, Xinhua added.


Astronomer Douglas Vakoch claimed the telescope could "lead to discoveries beyond our wildest imagination".

Qian Lei, a researcher with the National Astronomical Observatories of the Chinese Academy of Sciences, said: "The ultimate goal of FAST is to discover the laws of the development of the universe.

"In theory, if there is civilisation in outer space, the radio signal it sends will be similar to the signal we can receive when a pulsar (spinning neutron star) is approaching us."

Image: Engineers work on the colossal telescope in July 2015

Chinese state media said the location of the dish was chosen because there were no major towns nearby.

Hundreds of villagers who lived near the site have been forced to relocate and will be compensated with cash or housing.

State media said the relocation budget was £210m - more than the cost of the dish itself.

Following the launch of FAST, Chinese President Xi Jinping reportedly sent a congratulatory letter to the scientists and engineers who contributed to its construction.

The project is part of China's multi-billion pound space programme, which includes plans for a permanent orbiting space station and a manned mission to the moon.