The Sagittarius A* supermassive black hole, as seen by the Chandra X-ray Observatory. Nobody has yet seen the black hole directly NASA

LIKE a giant pale blue eye, the Earth stares at the centre of our galaxy. Through the glare and the fog it is trying to catch a glimpse of an indistinct something 30,000 light years away. Over there, within the sparkling starscape of the galaxy’s core… no, not those giant suns or those colliding gas clouds; not the gamma-ray glow of annihilating antimatter. No, right there in the very centre, inside that swirling nebula of doomed matter, could that be just a hint of a shadow?

Latest news: First ever real image of a black hole revealed

The shadow we’re straining to see is that of a monstrous black hole, a place where gravity rules supreme, swallowing light and stretching the fabric of space to breaking point. Black holes are perhaps the most outrageous prediction of science, and even though we can paint fine theoretical pictures of them and point to evidence for many objects that seem to be black hole-ish, nobody has ever actually seen one.

All that could change in the next few months. Astronomers are working to tie together a network of microwave telescopes across the planet to make a single instrument with the most acute vision yet. They will turn this giant eye towards what they believe is a supermassive black hole at the centre of our galaxy, code name Sagittarius A* (see image, above).

Even part-built, the microwave eye has already produced a hazy picture of Sagittarius A*. Last September, a …