Universe Expansion Calculator
Model cosmic expansion using Friedmann equations and cosmological parameters
Cosmological Parameters
Current expansion rate (67.7 or 73.4 km/s/Mpc)
Fraction of critical density in matter (~0.31)
Fraction of critical density in dark energy (~0.69)
Fraction of critical density in radiation (~0.00008)
Spatial curvature (0=flat, >0=closed, <0=open)
Time range for evolution plot
Universe Properties
Fundamental Properties
Density Components
Universe Characteristics
Model: ΛCDM cosmology with Friedmann equations
Current epoch: Radiation dominated
Total density: 100.00% of critical density
Scale Factor Evolution
ΛCDM Model Example
Our Universe Parameters
Hubble Constant: H₀ = 67.7 km/s/Mpc
Matter Density: Ωₘ = 0.3089 (30.89%)
Dark Energy Density: ΩΛ = 0.691 (69.1%)
Radiation Density: Ωᵣ = 0.0000824 (0.008%)
Curvature: Ωₖ = 0 (flat universe)
Universe Evolution
Early era (t < 50,000 years): Radiation dominated
Middle era (50,000 years < t < 9.8 Gyr): Matter dominated
Current era (t > 9.8 Gyr): Dark energy dominated
Current age: ~13.8 billion years
Future: Accelerating expansion toward heat death
Cosmic Epochs
Radiation Era
First 50,000 years
Photons and neutrinos dominate
Matter Era
50,000 years - 9.8 Gyr
Dark and baryonic matter dominate
Dark Energy Era
9.8 Gyr - present
Accelerating expansion
Cosmology Facts
Dark energy makes up ~69% of the universe
Dark matter comprises ~26% of all matter
Regular matter is only ~5% of the universe
The universe is geometrically flat (Ωₖ ≈ 0)
Expansion is currently accelerating
Understanding Universe Expansion
The Expanding Universe
Edwin Hubble discovered that distant galaxies are moving away from us, with more distant galaxies receding faster. This led to the understanding that space itself is expanding, described by the Hubble-Lemaître law: v = H₀d.
Friedmann Equations
- •Describe the expansion of homogeneous, isotropic universe
- •Relate expansion rate to energy density and pressure
- •Predict different expansion behaviors for different compositions
- •Account for matter, radiation, dark energy, and curvature
Cosmological Parameters
Ωₘ + ΩΛ + Ωᵣ + Ωₖ = 1
- Ωₘ: Matter density parameter (dark + baryonic matter)
- ΩΛ: Dark energy density parameter (cosmological constant)
- Ωᵣ: Radiation density parameter (photons + neutrinos)
- Ωₖ: Curvature parameter (geometry of space)
- H₀: Hubble constant (current expansion rate)
Critical Density: The density required for a flat universe. Each Ω parameter is the ratio of actual density to critical density.
Dark Energy Mystery
Dark energy is the most mysterious component of our universe. It causes the expansion to accelerate, contrary to what matter and radiation do. Its nature remains unknown, but it dominates the current cosmic budget.
- • Could be vacuum energy or a dynamic field
- • Responsible for accelerating expansion since ~5 Gyr ago
- • Will determine the ultimate fate of the universe
- • One of the biggest mysteries in modern physics
Universe Geometry
The curvature parameter Ωₖ determines the geometry of space. Current observations suggest our universe is very close to flat (Ωₖ ≈ 0), which has profound implications for cosmic evolution.
Flatness Problem: Why is the universe so close to critical density? This fine-tuning led to the theory of cosmic inflation.