World's biggest telescope puts Einstein to the test

Europe has agreed to fund the design of the world's biggest telescope, which will be the size of 200 football pitches and be able to see back in time to the astronomical equivalent of the Dark Ages.

The radio telescope will be called the Square Kilometre Array because it will be made up of dozens of radio dishes covering an area of one million square metres - 200 times bigger than Britain's biggest radiotelescope at Jodrell Bank.

Britain is one of the main backers of the decision to spend €38m (£27m) on the design of the telescope, which will enable astronomers to locate and weigh a billion galaxies as well as testing Einstein's general theory of relativity to its ultimate limit. "The range of science that the telescope will do is truly staggering, and will transform our understanding of the Universe," said Professor Philip Diamond of the University of Manchester, who is chairman of the telescope international steering committee. "It will address the big questions at the heart of science. What are the fundamental particles and forces? What are dark energy and dark matter? What is the origin of the observed structures in the Universe? How did planets like Earth form?" he said.

The Square Kilometre Array is one of the biggest international initiatives in science. It will involve hundreds of radioastronomers and engineers from all major European countries, along with America, Canada, India and China.

The Array will be so sensitive to the radiowaves from outer space that it should be able to pick up the faintest broadcasts from any intelligent civilisations living close to our nearest neighbouring stars.

Its many individual radio dishes will work in unison as if they are a single dish. The telescope will be so sensitive that it can only be built in a remote location where there is little radio interference from man-made sources - Argentina, Australia, China and South Africa are shortlisted for the site.

Radio telescopes detect long-wavelength radiation and can "see" parts of the sky that are not visible to more traditional optical telescopes. This includes the "dark ages" that formed about a billion years after the Big Bang when light was still interacting with matter, making the universe opaque.

"This represents a truly medieval cosmological period about which little is known," said Professor Steve Rawlings, head of astrophysics at Oxford University. "However, this was a crucial time for the universe because it was when matter coagulated into the first stars and galaxies. The universe then 'cleared' as light escaped from the congealing matter. The telescope will be able to peer through to this hazy time. We will thus obtain our first pictures of this mysterious epoch," he said.

Construction of the Square Kilometre Array is expected to be finished by 2020. It will be designed to study the radio emissions from hydrogen gas, which is the main constituent of stars and galaxies.