Stacks of carefully polished, coated and cut silicon wafers – normally used to manufacture integrated circuits – that will focus X-rays inside ESA’s Athena space observatory, due for launch in 2028.
Invisible X-rays tell us about the very hot matter in the Universe – black holes, supernovas and superheated gas clouds. But energetic X-rays do not behave like typical light waves – try to reflect them with a standard mirror and they are absorbed. Instead, X-rays can only be reflected at shallow angles, like stones skimming across water.
That means multiple mirrors must be stacked together to build a telescope. ESA has developed ‘silicon pore optics’ to see much further into space than the ageing XMM-Newton X-ray observatory. … (ESA)