- weight
- 0.57 g
- sun
- 6.6× wider
- sky
- warm white
Illustration computed from this world’s measured and derived values, not a photograph.
HIP 9618 b
HIP 9618 b is a confirmed Neptune-like exoplanet 220 ly from Earth in the constellation Aries, discovered in 2023 by Transiting Exoplanet Survey Satellite (TESS).
Transit: spotted by the tiny, repeating dip in its star’s light each time the planet crosses in front of it.
HIP 9618 b 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 6.6× wider than ours, bathing the cloud tops in warm white light. A year passes in just 21 days, and at an estimated 368°C (694°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 0.6 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 1,801 metres per second, 5.3 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 368°C (694°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 HIP 9618 b’s measured and computed values, not a real advisory.
How long to get there · 220 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 HIP 9618 b?
HIP 9618 b is a gas giant with no solid surface to stand on. At its cloud tops, gravity pulls about 0.57 times as hard as Earth's.
How far is HIP 9618 b from Earth?
HIP 9618 b lies about 220 light-years from Earth.
How long would it take to get to HIP 9618 b?
At the speed of NASA's Parker Solar Probe, the fastest craft ever built, the journey would take about 343,599 years.
How hot is HIP 9618 b?
HIP 9618 b's equilibrium temperature, the balance it reaches from its star's light alone before any greenhouse warming, is about 368°C (694°F).
How long is a year on HIP 9618 b?
HIP 9618 b completes one orbit of its star in 21 days.
Illustration generated from HIP 9618 b's confirmed parameters, not a photograph.