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NASA Exoplanets: Earth Comparison Calculator
x402
NASA Exoplanets: Earth Comparison Calculator is a paid API for AI agents from exoplanets-nasa.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-29).
Computes planet size, mass, density, surface gravity, and escape velocity as ratios to Earth, plus insolation if luminosity and orbital distance are provided.
Price / call$0.02
Success—
StatusUnknown
How this service works
Planet size, mass, density, gravity and escape speed as ratios to Earth, with insolation if luminosity and orbit are given.
Output
Returns a structured object with the planet's radius, mass, density (as ratio and in g/cc), surface gravity, escape velocity (as ratio and in km/s), size class label, a plain-language summary and verdict, and optionally insolation data if luminosity and orbit inputs were provided. Also includes the formulas used, any caveats, and flags for degraded or unchecked parameters.
Example use cases
Characterizing a newly confirmed super-Earth
“I just found a confirmed exoplanet that's 1.8 Earth radii and 6 Earth masses — can you calculate its surface gravity, escape velocity, and density compared to Earth, and tell me what size class it falls into?”
Estimating insolation alongside physical properties
“For a planet with radius 2.3 Earth radii and mass 10 Earth masses orbiting a star with 0.8 solar luminosities at 0.7 AU, give me all its Earth-comparison ratios including insolation.”
Screening a gas dwarf candidate
“Can you run Earth-comparison calculations for a planet that's 4 Earth radii and 15 Earth masses? I want to see its density and gravity ratio to understand if it could be rocky or gaseous.”
Technical details
Endpoint
GEThttps://exoplanets-nasa.x402tookit.com/earth-comparison?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need normalized, Earth-relative physical property comparisons for an exoplanet — specifically size, mass, density, gravity, and escape velocity as dimensionless Earth ratios. It is ideal for quickly characterizing newly discovered planets, building intuition about habitability or composition, or populating educational or research summaries. Prefer it over the habitable-zone or equilibrium temperature endpoints when the primary question is about physical properties rather than orbital climate context.
Side effects
- Missing required radiusEarth parameter returns a validation error
- radiusEarth outside range 0.05–30 may return an out-of-bounds error
- massEarth outside range 0.001–20000 may be rejected
- Providing orbitAu without luminositySolar (or vice versa) may result in insolation fields being null
- Invalid numeric types for query params cause schema validation failure
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Tags
x402
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