As the veteran 'Who' antagonists get ready for their close-up, we look back at 50 years of underwater history.
One of the greatest mysteries the James Webb Space Telescope (JWST) was developed to investigate was the birth of supermassive black holes (SMBHs). For more than twenty years, astronomers have puzzled over how these gravitational behemoths - weighing millions to billions of solar masses - could exist less than a billion years after the Big Bang. According to the most widely accepted cosmological models, massive black holes did not have enough time to form through the usual processes of black hole formation and mergers.

