Light delay — looking far = looking back · the finite speed of light

LIGHT DELAY SIMULATION

▸ Loading the constant c ≈ 299,792,458 m/s…

▸ Building the log distance axis: the Moon → the edge of the observable universe

▸ Calibrating real delays: the Moon 1.3 s · the Sun 8 min 20 s

▸ Placing targets: Mars · Proxima · Andromeda · CMB…

▸ Starting a light-wave pulse spreading at finite speed

▸ Ready — Online. ✅

Light delay clock

📡 Delay to target

Viewing—

Distance—

Light delay—

Looking back by—

Wavefront traveled—

Reached—

State—

Notes

Light has a finite speed c ≈ 300,000 km/s. Each target receives the light pulse after a delay = distance ÷ c. So the farther you look, the older the image — a telescope is a time machine looking into the past.

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Click 💡 Emit pulse to send a light wave spreading from Earth outward · click a target on the axis to view it & see the delay · pick a "Scenario" to change scale (seconds → years → millions/billions of years)

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Wavefront distance over time — log scale (the wave spreads at speed c) wavefront (log d)