The Noise That Gave Birth to Galaxies express
Quantum noise, like the hiss of an untuned radio, filled the infant Universe. Alan Guth showed that superfast expansion (inflation) caused this ripple to freeze, giving rise to clumps of matter — the seeds of galaxies.
A new method extends this picture to any theory of gravity. Previously, calculations only worked for Einstein's general theory of relativity; now they have been generalized to complex variants — with extra dimensions or dark energy, similar to those developed by Andrei Linde. It's like switching bands: each theory yields its own unique 'noise'.
The level of primordial noise decided the fate of the cosmos: had it been slightly different, black holes would have formed instead of stars. Now, by comparing calculations with satellite sky maps, we can for the first time hear exactly what kind of ethereal crackle created our world.
A slightly different level of quantum noise, and the Universe would consist solely of black holes.