01
A spectrum, not two boxes
Mass exists on a continuum — this page shows two representative cases, but intermediate masses follow intermediate paths.
Stars · Question
Why do some stars end quietly and others explode?
Every star begins the same way — a cloud of gas collapsing under its own gravity. What it becomes at the end depends almost entirely on one number: how much mass it started with.
Visual model
Two very different endings.
What's simplified
Real stellar evolution has more branches.
02
Timescales vary hugely
A Sun-like star lives roughly 10 billion years; a very massive star can burn out in just a few million — thousands of times faster.
Misconception check
Quick check.
Quick check
Go deeper
Keep exploring.
Next in this series →
Black holes ↗
Event horizon, accretion disk and gravity well.
Black holes
What is a black hole?
One possible ending for the most massive stars.
Universe
How big is the universe?
Zoom out from a single star to the whole observable universe.