Hubble's Law simulator Back

Hubble's Law simulator

Manipulate Hubble constant and galaxy distance to calculate recession velocity, redshift, and universe age in real time. Explore cosmic expansion and the mystery of recession velocities exceeding the speed of light.

parameters

Results
velocity v
v / c ratio
z
(1/H₀)
Hubble tension
Hubble Diagram
Hubble

: H₀ velocity-.: c.: .

🎓
." ".—.14,000 Mpc , from ( )."" .
🙋
I saw something about the "Hubble tension" in the news. What's the issue?
Theory & Key Formulas

$v = H_0 \cdot d$
$z = v/c$()
$t_H = 1/H_0$
$H_0 = 70$ km/s/Mpc → $t_H \approx 14$ Gyr
\lt section class="explanation"\gt \lt div class="bubble right"\gt \lt span class="bubble-icon"\gt 🎓 \lt div class="bubble-text"\gt 2 $H_0$ .Ia""73 km/s/Mpc,microwave(CMB) 67 km/s/Mpc..5σ""—energy . \lt div class="bubble"\gt \lt span class="bubble-icon"\gt 🙋 \lt div class="bubble-text"\gt How do we know the universe is about 13.8 billion years old? \lt div class="bubble right"\gt \lt span class="bubble-icon"\gt 🎓 \lt div class="bubble-text"\gt $t_H = 1/H_0$.$H_0 = 70$ km/s/Mpc 140.energy (Ωparameters)138.CMB temperature Pattern .

Frequently Asked Questions

energy ?

energy(Λ). 68%energy,27%,5%from (Ω_Λ≈0.68).H₀ , .

1 Mpc(mega) ?

1 pc()≈ 3.26.1 Mpc = 10⁶ pc ≈ 3.26 ≈ 3.09×10²² m.0.78 Mpc,5 Mpc, 14,000 Mpc.

""available?

460(),()available.""""—138 .inflation.

z ?

(v ≪ c) z ≈ v/c = H₀d/c. z = √((1+β)/(1-β)) - 1(β=v/c). a(t)z+1 = a()/a().z=1 100().

What is Hubble Law simulator?

Hubble Law simulator is a fundamental topic in engineering and applied physics. This interactive simulator lets you explore the key behaviors and relationships by directly manipulating parameters and observing real-time results.

By combining numerical computation with visual feedback, the simulator bridges the gap between abstract theory and physical intuition — making it an effective learning tool for students and a rapid-verification tool for practicing engineers.

Physical model & Key Equations

The simulator is based on the governing equations behind Hubble's Law simulator. Understanding these equations is key to interpreting the results correctly.

Each parameter in the equations corresponds to a slider in the control panel. Moving a slider changes the equation's solution in real time, helping you build a direct connection between mathematical expressions and physical behavior.

Real-World Applications

Engineering Design: The concepts behind Hubble's Law simulator are applied across mechanical, structural, electrical, and fluid engineering disciplines. This tool provides a quick way to estimate design parameters and sensitivity before committing to full CAE analysis.

Education & Research: Widely used in engineering curricula to connect theory with numerical computation. Also serves as a first-pass validation tool in research settings.

CAE Workflow Integration: Before running finite element (FEM) or computational fluid dynamics (CFD) simulations, engineers use simplified models like this to establish physical scale, identify dominant parameters, and define realistic boundary conditions.

Common Misconceptions and Points of Caution

model assumptions: The mathematical model used here relies on simplifying assumptions such as linearity, homogeneity, and isotropy. Always verify that your real system satisfies these assumptions before applying results directly to design decisions.

Units and scale: Many calculation errors arise from unit conversion mistakes or order-of-magnitude errors. Pay close attention to the units shown next to each parameter input.

Validating results: Always sanity-check simulator output against physical intuition or hand calculations. If a result seems unexpected, review your input parameters or verify with an independent method.

How to Use

  1. Set the Hubble constant (H₀) using h0slider or enter a value in h0ValNum between 60–75 km/s/Mpc, representing the current expansion rate of the universe
  2. Input the distance (d) via dslider or dValNum in megaparsecs (Mpc); typical galaxies range from 10–1000 Mpc for observational surveys
  3. Adjust h0bslider or h0bValNum to model alternative H₀ estimates from different measurement methods (Cepheid variables vs. CMB constraints), then observe how recession velocity v = H₀ × d changes across the parameter space

Worked Example

Consider a distant galaxy at d = 100 Mpc with H₀ = 70 km/s/Mpc (local value from Hubble Space Telescope calibration). The recession velocity is v = 70 × 100 = 7000 km/s, or approximately 0.023c. If tension-driven measurements yield H₀ = 73 km/s/Mpc (Cepheid-SN1a ladder), the same galaxy shows v = 7300 km/s, a 4.3% discrepancy highlighting the Hubble tension crisis affecting cosmological distance scales.

Practical Notes

  1. H₀ measurements from local anchors (SNe Ia, Cepheids) typically range 72–74 km/s/Mpc, while Planck CMB constraints suggest 67–68 km/s/Mpc; the 4.4σ tension drives the simulator's dual-slider design
  2. Redshift z can be recovered from recession velocity via z ≈ v/c at non-relativistic distances; for v > 0.1c, use the relativistic Doppler formula z = sqrt((1+β)/(1−β)) − 1 where β = v/c
  3. Systematic uncertainties dominate at d < 10 Mpc (peculiar motion contamination); use only d > 25 Mpc for robust H₀ inference in real cosmological surveys