Concept
The Big Bang
How everything began, 13.8 billion years ago.
The leading model for the origin of the universe: a hot, dense early state that has been expanding and cooling ever since. Supported by the cosmic microwave background, galaxy redshifts, and primordial element abundances.
What it is not
Not an explosion in space — space itself expanded (and still expands).
See also
Big Rip
An end-of-universe scenario where everything is torn apart.
Proper Motion
A star's drift across the sky over years.
Black Holes
Regions where gravity stops light itself.
Dark Matter
The invisible mass holding galaxies together.
Dark Energy
The mysterious force accelerating the universe.
Light-Year & Astronomical Distances
Measuring the unimaginable.