Two Flavors of Early Dark Energy Ease Cosmic Tension
Cosmologists faced a recipe problem: the universe's expansion rate measured nearby didn't match the rate deduced from the Big Bang's afterglow — the cosmic microwave background.
The Neutrino Soup Got a Little Colder Thanks to Ancient Waves
In the first moments after the Big Bang, the universe was a boiling soup of elementary particles. Even the light neutrinos were actively colliding with everything around. But the rapid expansion cooled this soup, and the neutrinos broke free, becoming almost indifferent to the surrounding world.
Stumbling Over Hubble Tension: How Primordial Black Holes Lose the Race for Dark Matter
In a recent study, astrophysicists showed how pre-recombination physics, particularly early dark energy, affects the spectral running $$α_s$$ and, consequently, the viability of scenarios forming primordial black holes from an ultra-slow-roll (USR) phase during inflation.