Stellar Evolution
Stellar Lifecycle
The 13-billion-year story of a star, told as you scroll — from a cold cloud of gas to the brilliant, violent, and strange ways stars die.
01 Molecular Cloud
It begins in the cold and dark
Stars are born inside giant molecular clouds — vast, frigid reservoirs of hydrogen and dust. A shockwave or gravitational nudge tips a region past balance, and it begins to collapse, fragmenting into dense knots that will each become a star.
02 Protostar
A core catches fire
As the knot collapses, it spins up into a flattened disk feeding a hot, glowing core. Infalling material and magnetic fields launch spectacular bipolar jets from the poles. The protostar isn't fusing yet — it glows from the sheer heat of contraction.
03 Main Sequence
The long, steady prime of life
Core temperature crosses ~15 million K and hydrogen fusion ignites for real. Outward radiation pressure balances inward gravity — a stable star is born. This equilibrium lasts almost the entire stellar lifetime; our Sun spends ~90% of its life right here.
04 Red Giant
The fuel runs low, the star swells
Core hydrogen exhausts. The core contracts and heats while hydrogen ignites in a shell around it — dumping so much energy that the outer layers balloon outward and cool to a deep red. When the Sun does this in ~5 billion years, it may reach Earth's orbit.
05a Low-Mass Fate
A gentle exit: white dwarf
Stars below ~8 solar masses never get hot enough to fuse past carbon. They shed their outer layers into a glowing planetary nebula, leaving behind a dense, Earth-sized ember — a white dwarf — that slowly cools over trillions of years. This is the Sun's destiny.
05b High-Mass Fate
A violent exit: supernova
Massive stars fuse elements all the way to iron — which costs energy instead of releasing it. Fusion stalls, the core collapses in under a second, and rebounds in a titanic shockwave. For weeks the explosion can outshine an entire galaxy, forging and scattering the heavy elements in your body.
06 The Remnant
What the collapse leaves behind
If the surviving core is 1.4–~3 solar masses, it becomes a neutron star — a city-sized sphere so dense a teaspoon weighs a billion tonnes. Above ~3 solar masses, nothing halts gravity: the core collapses to a singularity wrapped in an event horizon. A black hole is born.
07 Zoom Out
One cloud, many endings
Pull the camera back and the whole story fits on one line. Click any stage to fly back through the journey — every animation rewinds as you go.