Nasa engineers complete the unfolding of the James Webb space telescope

Time machine' will allow astronomers to study the beginning of the universe shortly after the Big Bang

Nasa engineers have completed the final unfolding of the huge primary mirror of the agency's James Webb space telescope. The manoeuvre was the final step of the $10bn observatory's two-week deployment phase that began with its launch on Christmas Day.

The telescope, which has already travelled more than 600,000 miles across space, is the largest, most powerful space telescope ever built and had to be folded up tightly so it would fit inside its Ariane 5 launch rocket.