- weight
- 3.08 g
- sun
- 0.12× as wide
- sky
- warm white
Illustration computed from this world’s measured and derived values, not a photograph.
HD 66428 c
HD 66428 c is a confirmed gas-giant exoplanet 174 ly from Earth in the constellation Monoceros, discovered in 2021 by Multiple Observatories.
Radial Velocity: spotted by the gravitational wobble the planet tugs in its star.
HD 66428 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 0.12× as wide as ours, bathing the cloud tops in warm white light. A year here lasts 28.7 Earth years, and at an estimated -178°C (-288°F) it is colder than almost anywhere in the solar system.
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 3.1 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 695 metres per second, 2 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.
- !Deeply frozen at around -178°C (-288°F), far below the freezing point of water.
- !There is nowhere to land: no ground, no deck, only cloud that thickens into crushing pressure.
- !Earth-similarity index 0.20: this world has almost nothing in common with our own.
A playful read of HD 66428 c’s measured and computed values, not a real advisory.
How long to get there · 174 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 66428 c?
HD 66428 c is a gas giant with no solid surface to stand on. At its cloud tops, gravity pulls about 3.1 times as hard as Earth's.
How far is HD 66428 c from Earth?
HD 66428 c lies about 174 light-years from Earth.
How long would it take to get to HD 66428 c?
At the speed of NASA's Parker Solar Probe, the fastest craft ever built, the journey would take about 271,031 years.
How hot is HD 66428 c?
HD 66428 c's equilibrium temperature, the balance it reaches from its star's light alone before any greenhouse warming, is about -178°C (-288°F).
How long is a year on HD 66428 c?
HD 66428 c completes one orbit of its star in 28.7 years.
Illustration generated from HD 66428 c's confirmed parameters, not a photograph.