- weight
- ≥ 0.98 g
- sun
- 1.4× wider
- sky
- deep orange
Illustration computed from this world’s measured and derived values, not a photograph.
HD 180617 b
HD 180617 b is a confirmed Neptune-like exoplanet 19.3 ly from Earth in the constellation Aquila, discovered in 2018 by Calar Alto Observatory.
Radial Velocity: spotted by the gravitational wobble the planet tugs in its star.
HD 180617 b is a giant ball of gas with no solid surface to stand on; you would simply sink into ever-thicker cloud. Its red dwarf looks 1.4× wider than ours, bathing the cloud tops in deep orange light. A year passes in just 106 days, and at an estimated -71°C (-96°F) it is deeply frozen.
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 · habitable zone
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 1,011 metres per second, 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.
- !Cold at about -71°C (-96°F), survivable only fully suited and heated.
- !There is nowhere to land: no ground, no deck, only cloud that thickens into crushing pressure.
- It orbits within the habitable zone, where a world could in principle hold liquid water.
A playful read of HD 180617 b’s measured and computed values, not a real advisory.
How long to get there · 19.3 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 HD 180617 b?
HD 180617 b is a gas giant with no solid surface to stand on. At its cloud tops, gravity pulls at least 0.98 times as hard as Earth's.
How far is HD 180617 b from Earth?
HD 180617 b lies about 19.3 light-years from Earth.
How long would it take to get to HD 180617 b?
At the speed of NASA's Parker Solar Probe, the fastest craft ever built, the journey would take about 30,066 years.
How hot is HD 180617 b?
HD 180617 b's equilibrium temperature, the balance it reaches from its star's light alone before any greenhouse warming, is about -71°C (-96°F).
Is HD 180617 b habitable?
HD 180617 b orbits inside its star's habitable zone, the range of distances where liquid water could be stable, and its Earth-similarity index is 0.56. That makes it worth studying, but it is not evidence of life: we have no measurement of its atmosphere, water, or surface.
How long is a year on HD 180617 b?
HD 180617 b completes one orbit of its star in 106 days.
Illustration generated from HD 180617 b's confirmed parameters, not a photograph.