Slide the altitude control to watch five real atmospheres - Venus, Earth, Mars, Jupiter, and Titan - thin out at their own real published rate, and read what fraction of surface pressure is left at each height.
Every column uses the same real barometric relationship - pressure falls off exponentially with height - but each world's own scale height (how fast that fall-off happens) comes from its own temperature, gravity, and gas mix. Drag to orbit and scroll or pinch to zoom on the scene above.
Planet Atmosphere Scale-Height 3D Explorer
Drag the altitude control on this browser explorer to compare how fast Venus, Earth, Mars, Jupiter, and Titan's real atmospheres thin out with height - each world decays at its own published rate.
Scale height is the altitude over which pressure drops by a factor of e
Every atmosphere in the solar system follows the same barometric relationship: pressure falls off roughly exponentially with altitude, and the height over which it drops by a factor of about 2.72 (Euler's number, e) is the scale height. The formula is H = kT / (M g), where T is temperature, M is the average mass of one gas molecule, and g is surface gravity. A hot, light-molecule, low-gravity atmosphere therefore puffs up into a large scale height, while a cold, heavy-molecule, high-gravity one stays thin. That single number is what this explorer compares across five worlds.
What the altitude slider controls
- Altitude slider (0 to 90 km) moves a shared probe plane across all five columns at once
- Each column's opacity fades with height following that world's own real e^(-altitude/scale height) decay curve
- A facts panel and comparison table show each world's real scale height and the percentage of surface (or 1-bar) pressure remaining at the current altitude
- Jupiter's "ground" disk marks the 1-bar reference level used for gas giants, not a solid surface
- Titan's wider published range (15-50 km) and why it differs from the other four worlds is disclosed directly in the panel
- Drag to orbit, scroll or pinch to zoom
- Runs fully in the browser with the vendored three.js engine - no account, no upload
The five worlds' published figures
| World | Scale height | Surface temperature | Surface gravity | Surface (or 1-bar) pressure |
|---|---|---|---|---|
| Venus | 15.9 km | about 735 K | 8.87 m/s^2 | about 92 bar |
| Earth | 8.5 km | 288 K | 9.8 m/s^2 | 1013 mb (1 bar) |
| Mars | 11.1 km | about 210 K | 3.71 m/s^2 | 6.36 mb |
| Jupiter (1-bar level) | 27 km | about 165 K | 24.79 m/s^2 | 1 bar (reference) |
| Titan | about 20 km (range 15-50 km) | 94 K | 1.35 m/s^2 | about 1.5 bar |
Mars's 6.36 mb surface pressure is about 0.6% of Earth's. Every figure above is real and independently published by NASA's NSSDCA planetary fact sheets (Earth, Venus, Mars, Jupiter); Titan's sources are cited below.
Why the Jupiter and Titan numbers carry a caveat
Two of the five worlds need a footnote. Jupiter's 27 km is measured at the standard 1-bar reference level, because Jupiter has no solid surface to measure from. And Titan, Saturn's moon, has no single settled number: its stratosphere is warmed by haze far more than the other four worlds' near-surface layers are, so published sources (cross-referenced from Wikipedia's "Atmosphere of Titan" summary of Cassini and Huygens-era atmospheric-structure work) give a range of roughly 15 to 50 km depending on altitude. This scene uses 20 km, the commonly-cited near-surface estimate.
Related atmosphere explorers on this site
For Earth's own named atmosphere layers and the Karman-line space-boundary convention, see the Karman Line Atmosphere Layers 3D Explorer. For a real telescope detecting individual molecules in a distant exoplanet's atmosphere, see the Exoplanet Atmosphere Spectroscopy 3D Explorer. For Jupiter's own banded clouds and Great Red Spot, see the Gas Giant Atmosphere 3D Explorer.
Limits of this teaching approximation
The atmosphere columns and the altitude probe are drawn straight on your own device with WebGL - the figures and decay curves never leave your browser and nothing is uploaded to a server. The 3D engine downloads a single time (about 0.7 MB) and is then cached, so re-dragging the altitude slider starts instantly. Real atmospheres do not decay as one perfect exponential all the way up - temperature and composition change with altitude, especially on Titan - so this scene uses a single fixed near-surface scale height per world as a teaching simplification.
Frequently Asked Questions
What is atmospheric scale height?
It is the altitude over which a planet's atmospheric pressure drops by a factor of about 2.72 (e). It follows from the formula H = kT / (M g), where T is temperature, M is the average gas-molecule mass, and g is surface gravity.
What is Earth's real scale height?
About 8.5 km, per NASA's NSSDCA Earth fact sheet (surface temperature 288 K, gravity 9.8 m/s^2, surface pressure 1013 mb).
Why does Jupiter have a bigger scale height than Earth even though it's colder at the 1-bar level?
Jupiter's atmosphere is almost entirely light hydrogen and helium (about 89.8% H2, 10.2% He), and a lighter average molecule mass raises the scale height even at a lower temperature - giving Jupiter 27 km at its 1-bar reference level versus Earth's 8.5 km.
Why is Titan's scale height shown as a range instead of one number?
Published sources give roughly 15 to 50 km depending on altitude, because Titan's stratosphere is warmed by haze absorption far more than the other four worlds' near-surface layers are. This scene uses 20 km, the commonly-cited near-surface estimate.
What does "0 km" mean for Jupiter if it has no solid surface?
It is the standard 1-bar reference level astronomers use as Jupiter's "surface" for atmospheric measurements, not a solid ground.
Why is Venus's atmosphere so much denser than Earth's?
Venus's surface pressure is about 92 bar - roughly 92 times Earth's - mostly carbon dioxide (about 96.5%), at a surface temperature around 735 K.
What does the altitude slider actually change?
It moves a shared probe plane across all five columns and recalculates, for each world, the percentage of its own surface (or 1-bar) pressure remaining at that height using its real published scale height.
Where do these figures come from?
NASA's NSSDCA planetary fact sheets for Earth, Venus, Mars, and Jupiter, and, for Titan, Wikipedia's "Atmosphere of Titan" summary of published Cassini and Huygens-era atmospheric-structure work - all cross-checked against the H = kT / (M g) relationship.