- weight
- ≥ 0.97 g
- sun
- 14.2× wider
- sky
- deep orange
Illustration computed from this world’s measured and derived values, not a photograph.
Gl 378 b
Gl 378 b is a confirmed Neptune-like exoplanet 48.8 ly from Earth in the constellation Ursa Major, discovered in 2019 by Haute-Provence Observatory.
Radial Velocity: spotted by the gravitational wobble the planet tugs in its star.
Gl 378 b is a giant ball of gas with no solid surface to stand on; you would simply sink into ever-thicker cloud. Its orange dwarf looks 14.2× wider than ours, bathing the cloud tops in deep orange light. A year passes in just 3.8 days, and at an estimated 557°C (1034°F) it is furnace-hot.
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 2,049 metres per second, 6 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.
- !Furnace-hot at around 557°C (1034°F), with no liquid water and no shade anywhere.
- !There is nowhere to land: no ground, no deck, only cloud that thickens into crushing pressure.
A playful read of Gl 378 b’s measured and computed values, not a real advisory.
How long to get there · 48.8 ly away
No other confirmed planets here yet. New ones auto-appear as telescopes report.
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 Gl 378 b?
Gl 378 b is a gas giant with no solid surface to stand on. At its cloud tops, gravity pulls at least 0.97 times as hard as Earth's.
How far is Gl 378 b from Earth?
Gl 378 b lies about 48.8 light-years from Earth.
How long would it take to get to Gl 378 b?
At the speed of NASA's Parker Solar Probe, the fastest craft ever built, the journey would take about 76,070 years.
How hot is Gl 378 b?
Gl 378 b's equilibrium temperature, the balance it reaches from its star's light alone before any greenhouse warming, is about 557°C (1034°F).
How long is a year on Gl 378 b?
Gl 378 b completes one orbit of its star in 3.8 days.
Illustration generated from Gl 378 b's confirmed parameters, not a photograph.