When light passes through a transparent material, a small share of it scatters in a new direction and comes out at a slightly different wavelength, which means a different colour. C. V. Raman and his student K. S. Krishnan found this in 1928 using a spectrograph they built themselves, and it was named the Raman effect. Each material shifts light by its own specific amounts, so the scattered light acts like a fingerprint of the molecules inside. Scientists now use this to identify chemicals, check medicines and study the structure of materials without destroying them. Raman won the Nobel Prize in Physics in 1930.

Israeli reports also say the cabinet directed the military to prepare for a possible new attack on Iran.

Angkor, near Siem Reap in northern Cambodia, was the capital of the Khmer Empire, which ruled much of mainland Southeast Asia between roughly the 9th and 15th centuries. At its height the city spread across about 3,000 square kilometres, making it the largest pre-industrial city on Earth by area. Its growth depended on water: huge reservoirs called barays, along with canals and embankments, stored monsoon rain and carried it to rice fields. That system let farmers harvest more than once a year and fed a very large population through the dry season. The temple complex of Angkor Wat, built in the early 12th century, is the best-known monument and still stands at the heart of the park.