Lambda-CDM Model Explorer
Build Your Own Universe:
Visualising the Composition and Fate of the Cosmos.
Cosmic Composition Simulator
The Cosmic Ingredients
The Lambda-CDM Model is cosmology’s standard model, explaining the universe from the Big Bang to today.
It posits that the universe is made of three key components whose densities ($\Omega$) dictate its fate: Baryonic Matter (the visible stuff—stars, planets, us), Cold Dark Matter (CDM) (an invisible mass that provides the gravitational scaffolding for galaxies), and Dark Energy ($\Lambda$) (an anti-gravitational force driving accelerated expansion).
This tool allows you to set the starting ratios of these mysterious components.
Structure Formation
Despite being invisible and non-interacting, Cold Dark Matter (CDM) is crucial. Gravity causes CDM to slowly clump together, forming an invisible cosmic web or scaffolding.
Normal (Baryonic) matter then falls into these deep gravitational wells, giving rise to all the visible structures we observe—galaxies, clusters, and superclusters.
When you increase the CDM percentage in the simulation, watch how the initial particle distribution rapidly forms tighter, denser clusters.
Dark Energy and Cosmic Fate
Dark Energy ($\Lambda$) acts as a constant, uniform pressure on the universe, causing its expansion to accelerate. If Dark Energy dominates (high $\Lambda$), the structure formation stalls, and the universe flies apart faster and faster, potentially leading to a “Big Freeze.”
If Dark Matter dominates, the expansion slows or might eventually reverse into a “Big Crunch.” Use the Dark Energy Slider to control the expansion rate and observe how this mysterious force determines the ultimate fate of the simulated cosmos.
