- weight
- ≥ 0.95 g
- sun
- 4.7× wider
- sky
- warm white
Illustration computed from this world’s measured and derived values, not a photograph.
HD 20003 c
HD 20003 c is a confirmed Neptune-like exoplanet 136 ly from Earth in the constellation Hydrus, discovered in 2019 by La Silla Observatory.
Radial Velocity: spotted by the gravitational wobble the planet tugs in its star.
HD 20003 c is a giant ball of gas with no solid surface to stand on; you would simply sink into ever-thicker cloud. Its yellow, Sun-like star looks 4.7× wider than ours, bathing the cloud tops in warm white light. A year passes in just 34 days, and at an estimated 301°C (573°F) it is blistering.
How closely this world matches Earth in size and warmth, from 0 to 1 (Earth = 1.0). Computed by gravityfinder. See every world ranked →
What these mean: surface gravity · tidal locking · equilibrium temperature · Earth similarity
If your children grew up herea playful thought experiment
There is no ground here to grow up on, only bottomless sky. A child could never stand, walk, or even fall to a surface, because there isn't one. Under about 1.0 times Earth's gravity and pressure that only climbs the deeper you go, anything built for this world would not look human at all: picture something closer to a deep-sea creature than a person, broad and buoyant, drifting through the cloud decks with no need for legs and no floor to land on.
- Body plan
- Floating, not upright
- With no surface and no fixed up or down, a skeleton built for standing would be useless; a drifting, gas-filled body would not.
- Build
- Broad and pressure-hardened
- Pressure rises without limit toward the interior, so anything alive would have to be built like a deep-sea animal, not a land one.
A playful thought experiment from this world’s gravity, not a prediction about any real person. No human has ever grown up off Earth, so no one truly knows; the direction (taller in low gravity, shorter and stockier in high) follows how growing bodies respond to weight.
Hear how a voice sounds herea computed acoustic demo
Your voice would sound a thin, helium-fast squeak.
There is no surface to stand on; this is the sound at the cloud tops, where the air is mostly hydrogen and helium, the lightest gases there are. Sound races through them at about 1,704 metres per second, 5 times its Earth speed, flipping a voice into a thin, cartoon-helium squeak. The temperature behind that number is this world's computed equilibrium temperature; its real atmosphere is unknown. The demo plays the shift capped at 1.8x; the real effect would be even stronger.
A real voice sample, pitch-shifted (tempo held constant) to suggest the acoustics: a playful approximation, not a precise simulation. Voice: Lingua Libre / Vealhurl, CC BY-SA 4.0.
- !Blistering at about 301°C (573°F), far too hot for liquid water on the surface.
- !There is nowhere to land: no ground, no deck, only cloud that thickens into crushing pressure.
A playful read of HD 20003 c’s measured and computed values, not a real advisory.
How long to get there · 136 ly away
Zoom out: star → system → (soon) galaxy arm, host black hole, and a real image of the host galaxy.
Matched telescope & eyepiece recommendations are coming. Any product links will carry a clear affiliate disclosure.
What is the gravity on HD 20003 c?
HD 20003 c is a gas giant with no solid surface to stand on. At its cloud tops, gravity pulls at least 0.95 times as hard as Earth's.
How far is HD 20003 c from Earth?
HD 20003 c lies about 136 light-years from Earth.
How long would it take to get to HD 20003 c?
At the speed of NASA's Parker Solar Probe, the fastest craft ever built, the journey would take about 212,787 years.
How hot is HD 20003 c?
HD 20003 c's equilibrium temperature, the balance it reaches from its star's light alone before any greenhouse warming, is about 301°C (573°F).
How long is a year on HD 20003 c?
HD 20003 c completes one orbit of its star in 34 days.
Illustration generated from HD 20003 c's confirmed parameters, not a photograph.