COSMOLOGICAL COUPLING

A new hypothesis suggests the universe's expansion could be causing all material objects to grow in mass. The universe's black holes are bigger than astrophysicists expected them to be. Now, a new study suggests why: Every single black hole may be growing as the universe expands. The new hypothesis, called "cosmological coupling", argues that as the universe expands outward after the "Big Bang", all objects with mass grow with it too. And black holes, as some of the most massive objects known to exist, grow the most. The ballooning masses of black holes aren't a result of anything they're gorging on but are instead somehow thethered to the universe itself. This would mean that all of the universe's black holes-including the merging black holes detected in gravitational wave experiments, the wandering black holes at the outskirts of our galaxy and even the supermassive black holes at the centers of most galaxies- are growing over time. If the researchers are correct, it means everything with mass is getting bigger-suns, neutron stars, planets and even humans. Of course, this coupling would be much weaker for us than for black holes. The energy of light is said to be cosmologically coupled with the universe's expansion, losing energy as they do so. Cosmological coupling does apply to other objects and material in the universe, but the strength of the coupling is so weak that you cannot see its effects. Sizes of black holes are determined by observing gravitational waves, or gigantic ripples in the fabric of space-time emitted when massive objects oscillate.