The Big Bang is the prevailing model for the origin of the universe, describing how it expanded and cooled from an extremely hot, dense state about 13.8 billion years ago. It is not an explosion in space but an expansion of space itself. The model's successes include the cosmic microwave background, the observed abundances of hydrogen and helium forged in the first minutes, and the large-scale distribution of galaxies.
Cosmology · Dark Matter · Black Holes
Stars cannot leave a black hole lighter than the Sun. In late 2025 a gravitational-wave detector caught a signal hinting at exactly that, possibly a r...
Cosmology · Early Universe · Cosmic Microwave Background
Everywhere you point a radio dish, a faint glow answers back: the cooled afterglow of the Big Bang, released when the universe was 380,000 years old. ...
Cosmology · Particle Physics · Big Bang
The Big Bang should have made matter and antimatter in perfectly equal amounts, and they should have annihilated each other completely, leaving a univ...
Cosmology · Early Universe · First Stars
The first stars formed from pure hydrogen and helium, with no heavier element to cool the gas, so theory says they grew enormous, burned hot, and died...
Cosmology · Early Universe · Galaxy Formation
At a redshift of 14.44, MoM-z14 is the farthest galaxy ever confirmed: a bright, nitrogen-rich beacon that switched on just 280 million years after th...
Astrophysics · Particle Physics · Big Bang Nucleosynthesis
A free neutron has a half-life of approximately ten minutes and eleven seconds. Inside an iron nucleus, the same particle is essentially immortal. The...