Desktop cosmos: Small is beautiful for big physics

 作者:展吡攻     |      日期:2019-03-14 06:07:05
By Matthew Chalmers IN THE control centre on the Hanford Nuclear Reservation in Washington state, banks of plasma screens await a signal that might never come. Hope springs from two concrete tubes that stretch out at right angles from the control centre and extend 4 kilometres towards the horizon. Inside them, laser beams ping relentlessly back and forth. The site is one of two that make up the Laser Interferometer Gravitational-Wave Observatory, LIGO, the largest experiment so far for spying the ripples in space-time known as gravitational waves. Off the coast of west Africa, perched on the highest point of the Canary Islands, a gamma-ray telescope called MAGIC – the name stands for the Major Atmospheric Gamma-ray Imaging Cherenkov telescope – scans the heavens for bursts of high-energy photons from far corners of the universe. Every now and again it catches a fleeting glimpse of something. Seconds, perhaps, of activity are followed by silence again. Back in the US, meanwhile, teams work flat out on plans for a $650 million space probe called the Joint Dark Energy Mission. It is just the latest and most ambitious bid to study how the universe is expanding and tell us what the vast bulk of the cosmos is made of. These are just three of many experiments that could deliver breakthroughs in our understanding of nature’s most enigmatic force, gravity. If so, they will do it in the traditional way of big physics, with large collaborations and hefty bank balances. But that might not be the only way. If ideas being explored by a good few physicists are right,