Main Sequence: Hydrogen fusion in the core
balances gravity. A 20 M☉ star burns for ~10 million years.
💥 Supernova
About this simulation
A supernova is the cataclysmic explosion of a massive star at the end
of its life, briefly outshining an entire galaxy. This simulation
traces a star through its whole lifecycle — from steady hydrogen
burning to the collapse of its iron core and the blast that scatters
newly forged elements across space. Supernovae are how the carbon,
oxygen, and iron in our bodies and planet were created, making them
one of the most important processes in cosmic chemical evolution.
How it works
On the main sequence the star fuses hydrogen, and outward pressure
balances gravity.
Fuel runs out, the star swells into a red supergiant, and an inert
iron core builds up at its centre.
When the iron core exceeds the Chandrasekhar limit it collapses in
under a second to nuclear density and rebounds.
A neutrino-driven shockwave blasts the envelope outward; what is
left behind becomes a neutron star or a black hole.
Key equations
M_Ch ≈ 1.4 M☉ — the Chandrasekhar limit, the maximum mass
an electron-degenerate core can support before collapse;
E ≈ 10^46 J — total energy released, ~99% carried away by
neutrinos.
Controls
Phases — jump to any stage of stellar evolution.
Mass — set the progenitor mass (8–100 M☉); above
~25 M☉ the remnant is a black hole.
Explode! — trigger the supernova blast and ejecta.
Reset — return the star to the main sequence.
Pause / Play — freeze or resume the animation.
Auto — let the star evolve through all phases automatically.
Did you know?
For a few seconds a core-collapse supernova releases more energy in
neutrinos than all the stars in the observable universe emit in light
combined — yet those ghostly particles pass through you by the
trillions, completely unnoticed.
About this simulation
This simulation renders a Type Ia or Type II supernova as a real-time WebGL fragment shader rather than a solved hydrodynamic model. A single progress value (0→1) driven by the Explode button expands a shock-front radius proportional to energy × progress, while a five-octave fractal Brownian motion (fBm) noise field warps the ejecta shell into ragged, turbulent filaments instead of a smooth sphere. Each pixel's colour comes from a temperature ramp — red, through orange and white, to blue — shifted hotter for Type Ia and redder for Type II. The progenitor mass slider feeds a simple threshold rule, echoing the real Chandrasekhar limit, that decides whether the collapsing core leaves behind a neutron star or a black hole.
What it shows
A star's collapse and rebound rendered as an expanding shock ring, a turbulent noise-driven ejecta shell, and a bright core flash that cools from white through orange to red as the explosion's progress variable advances from 0 to 1, ending in a small glinting remnant dot.
How to use it
Pick Type Ia or Type II, set the progenitor mass, energy/brightness, and expansion-speed sliders, then press Explode! to trigger the blast. Use Pause to freeze a frame, Reset to return to the pre-explosion star, or Auto to loop the whole cycle automatically.
Did you know?
For the real 1987A supernova, a burst of neutrinos was detected on Earth about three hours before the light from the explosion arrived — because neutrinos escape the collapsing core almost instantly, while photons take hours to fight their way out through the star's dense envelope.
Frequently Asked Questions
Is this simulation solving real stellar physics equations, or is it an animation?
It is a stylized, real-time WebGL fragment shader, not a hydrodynamic or nuclear-physics solver. A single progress value (0 to 1) drives a shock-front radius, a fractal-noise ejecta shell, and a temperature-to-colour ramp, and the mass slider feeds a simple threshold rule inspired by the Chandrasekhar limit. It reproduces the qualitative sequence of a real supernova — shock breakout, peak brightness, cooling ejecta, remnant — without integrating the underlying differential equations.
What determines whether the remnant is a neutron star or a black hole?
The simulator applies a simple rule: if the progenitor mass slider is set to 25 solar masses or more, the remnant is labelled a black hole; below that it is labelled a neutron star. This echoes the real astrophysical idea that above roughly 20–25 solar masses a collapsing iron core is thought to be too massive for the neutron-degeneracy pressure that supports a neutron star to halt further collapse.
What is the difference between Type Ia and Type II supernovae in this simulator?
The Type selector shifts the shader's temperature ramp: Type Ia (white-dwarf thermonuclear detonation) is rendered slightly hotter and whiter, while Type II (core-collapse) is rendered slightly redder, matching the real observational difference in their spectra and light curves. In reality Type Ia comes from a white dwarf that accretes past the Chandrasekhar limit and detonates entirely, while Type II comes from the core collapse of a single massive star that keeps its outer envelope.
What do the energy and expansion-speed sliders actually control in the shader?
Energy/brightness scales the shock-front radius, the ejecta shell's brightness, and the core flash intensity in the fragment shader (shockR = progress × 1.4 × energy). Expansion speed scales how fast the 0-to-1 progress variable advances each frame, so it compresses or stretches the whole explosion timeline without changing its shape.
Why does the ejecta shell look ragged and filamentary instead of a smooth expanding sphere?
The shell brightness is multiplied by a five-octave fractal Brownian motion (fBm) noise field sampled in polar coordinates around the shock radius, which breaks up what would otherwise be a perfectly smooth ring into turbulent, ragged filaments. This mirrors real supernova remnants such as the Crab Nebula or Cassiopeia A, whose ejecta are famously clumpy and filamentary rather than uniform shells, a result of real hydrodynamic (Rayleigh–Taylor) instabilities.