(Image: W W Norton)
NINETY-FIVE per cent of the universe is made of invisible stuff: the dark matter that holds the galaxies together and the dark energy that causes space to expand at a quickening pace. There is no shortage of theoretical candidates for these elusive ghosts. But how are astronomers to look for things that can’t be seen?
That’s where “Einstein’s telescope” comes in. It’s a term Evalyn Gates gives to gravitational lensing, the process by which a massive object distorts light that is streaming by, producing spectacular optical illusions in the sky and revealing the presence of…
