EnvironmentDoes oil-rich Saudi Arabia really want to mend its ways and go green? The desert kingdom’s much-hyped, zero-carbon linear city has been dismissed as greenwashing, but there is some truth to the claim the country wants to be more sustainable, finds Graham Lawton Comment
PhysicsCan recreating black holes in the lab solve the puzzles of space-time? Researchers are building models of everything from black holes to the big bang in tanks of liquid. Now some claim these surprisingly simple models are showing us where our theories of space-time are wrong Features