Is this the same as looming or superior mirages?

No. Superior mirages happen when cooler air sits under warmer air (inversion), bending rays downward so objects appear elevated. Here the hot surface creates the opposite gradient class, producing inferior mirages.

Why does the model use n sin θ = const?

For horizontal layers Snell’s law applied infinitesimally implies that quantity stays fixed along the path — the continuous analogue of discrete layer Snell stepping.

Can I get quantitative deflection angles for a real highway?

You would need measured temperature and density profiles. This page uses a tunable gradient for illustration, not meteorological data.

Does turbulence matter?

Yes in practice: shimmering near hot surfaces comes from time-varying pockets of air. The simulator uses a smooth profile only.

Inferior Mirage (hot road)

n(y) gradient above hot asphalt: rays bend — sky light looks like a wet patch.

About this model

On hot roads the air density drops sharply near the surface, so the refractive index n(y) increases with height y. In a horizontally stratified model, n(y) sin θ is conserved along a ray, so light from the sky can curve upward into an observer’s line of sight, creating a bright “wet” patch that is really a distorted image of the sky — an inferior mirage. The simulator traces rays through a linear n(y) profile above the asphalt and draws a simple layered background. It is not a full computational fluid dynamics or radiative transfer model; mirages also occur with temperature inversions (superior mirages) which are not shown here. The goal is to connect gradients in index to ray curvature qualitatively and to motivate why grazing sight lines are most affected.

Who it's for: Introductory geometric optics and atmospheric physics students learning that Snell’s law in layers explains curved rays without “new physics.”

Key terms

Inferior mirage
Refraction
Atmospheric gradient
Refractive index
Ray bending
Sky light
Stratified medium
n sin θ invariant

How it works

Inferior mirage: a strong temperature gradient above hot asphalt lowers refractive index with height so light can bend and bring sky light to the eye along the road.

Frequently asked questions

Is this the same as looming or superior mirages?: No. Superior mirages happen when cooler air sits under warmer air (inversion), bending rays downward so objects appear elevated. Here the hot surface creates the opposite gradient class, producing inferior mirages.
Why does the model use n sin θ = const?: For horizontal layers Snell’s law applied infinitesimally implies that quantity stays fixed along the path — the continuous analogue of discrete layer Snell stepping.
Can I get quantitative deflection angles for a real highway?: You would need measured temperature and density profiles. This page uses a tunable gradient for illustration, not meteorological data.
Does turbulence matter?: Yes in practice: shimmering near hot surfaces comes from time-varying pockets of air. The simulator uses a smooth profile only.

Continue with similar topics in this category — or all 50 in Optics & Light.

View category →

FeaturedSchool

Refraction

Launch Simulator

Light crossing boundaries. Snell's law with angle measurements.

NewSchool

Prism & Dispersion

Launch Simulator

White light through a prism creating a rainbow spectrum.

NewSchool

Fiber Bend & TIR Loss

Launch Simulator

Curved core: outer-wall incidence vs θ_c; tight R leaks (meridional sketch).

NewSchool

Chromatic Aberration

Launch Simulator

Cauchy n(λ); thin-lens f(λ); paraxial rays R/G/B.

NewSchool

Fermat's Principle

Launch Simulator

OPL = n₁AP+n₂PB vs hit point; minimum = Snell path.

NewSchool

Fiber: Numerical Aperture

Launch Simulator

NA from n_core, n_clad; acceptance angle and bend loss cue.

Inferior Mirage (hot road)

About this model

How it works

Frequently asked questions

Related simulators

Refraction

Prism & Dispersion

Fiber Bend & TIR Loss

Chromatic Aberration

Fermat's Principle

Fiber: Numerical Aperture

Inferior Mirage (hot road)

About this model

How it works

Frequently asked questions