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Cosmology
Two of the universe's most enigmatic phenomena may be intimately linked
Black holes-objects so dense that nothing can escape their pull-are among the most eye-catching predictions of general relativity, a model of gravitational attraction proposed by Albert Einstein over a century ago. They squat invisibly in the middle of galaxies, feasting on stars and interstellar debris.
They are also a clear indicator that general relativity's days as gravity's best explanation are numbered. That theory says a black hole's core is a point of infinite density and pressure called a singularity. This, says Chris Pearson at ral Space, Britain's national laboratory for space research, is a mathematical impossibility.
A host of more palatable alternatives have been proposed, but none has the observational evidence needed to back it up....