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Reality guide: Six radical ideas to change physics

作者:余尾    发布时间:2019-02-26 02:12:07    

Heather O'brien/EyeEm/Getty By Stuart Clark and Richard Webb Our understanding of the universe has been completely rewritten in the past century – and the obvious gaps we still have in our understanding mean it is likely to be rewritten again. But what ideas provide possible ways forward? Here we explore some of the most promising. For the lowdown on our current best theories of the universe, take a look at Reality guide: The essential laws of cosmology and Reality guide: The essential laws of quantum physics To read more about the outstanding problems in physics today, turn to Reality guide: Six problems physics can’t explain Our theories of gravity have only ever been tested on small scales General relativity is a hugely accurate theory of gravity – as far as we can tell. But could modifying gravity perhaps exorcise some cosmic demons? General relativity’s predictions of the movements of probes and planets are accurate up to the scale of the solar system, and the recent discovery of gravitational waves indicates it predicts spot-on what happens when two orbiting black holes merge, too. But by cosmic standards, these systems have a lot of mass crammed into a relatively small space.  What happens to gravity in environments where its strength is weaker? A tweaked version of gravity called modified Newtonian dynamics (MOND), might describe the anomalous galactic rotations taken to be evidence for dark matter, but there is as yet no theory for how this modification might come about. The DGP gravity hypothesis, meanwhile, named after the initials of its originators,

 

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