It would be hard to find two less likely places to party. One was the Karoo, a South African desert. The other was Murchison, an Australian county so remote that it does not possess a town. But at both yesterday officials from eight countries gathered to mark an extraordinary moment in science. 

Building work was starting on the Square Kilometre Array telescope - SKA for short. When finished, its 197 dishes and 130,000 antennae will be eight times more sensitive than existing telescopes. It will be able to map the sky 135 times faster.

According to Dr Danny Price from the Curtin Institute of Radio Astronomy, it "could detect a mobile phone in the pocket of an astronaut on Mars, 225 million kilometres away". And if there are intelligent beings with technology like ours, it could detect radiation from their radio and telecommunication networks.

Scientists hope it will allow us to look billions of years back to when the first stars were forming. This should help us work out how galaxies take shape.

They also hope that the radio waves from dead stars will provide a deeper understanding of gravity. "Fast radio bursts", which produce the equivalent of a year's energy from the sun in a fraction of a second, will be investigated too.

The SKA's two sites have different purposes. The Australian site has been named SKA-Low because its antennae are sensitive to low-frequency radio signals. The South African site, SKA-Mid, will collect signals on higher frequencies.

According to SKA-Low's director, Dr Sarah Pearce, the observatory will "define the next 50 years for radio astronomy, charting the birth and death of galaxies, searching for new types of gravitational waves and expanding the boundaries of what we know about the universe".

The data collected will be processed by computers in Britain. The team running it expect to receive 600 million gigabytesA unit of storage capacity. Researchers calculate this statistic by assigning rough values in these terms to words as well as computer data. of data a year.

There have been few comparable projects in human history. The Large Hadron ColliderThe world's most powerful machine for smashing high-energy particles together. built by the European Organisation for Nuclear Research involved over 10,000 scientists from more than 100 countries. The International Space StationA joint project between the US, Russia, Japan, Canada and the European Space Agency. was created by the space agencies of the US, Russia, Europe, Japan and Canada.  

Yes: The universe is so vast that we cannot be alone, but previous radio telescopes have not been powerful enough to pick up radiation from alien telecom systems. This will be our best ever hope.

No: We will do exactly the opposite. With this super-telescope we will conduct a search of the universe on a colossal scale, and finally establish beyond reasonable doubt that aliens do not exist.

Or... We are very likely to find some evidence of intelligent life outside our universe, but there is no reason to believe that it would respond. Sensible aliens would want nothing to do with us.