What it’s like to stand here
ZTF J1828+2308 b
weight
51.31 g
sky
icy blue-white

Illustration computed from this world’s measured and derived values, not a photograph.

ZTF J1828+2308 b

ZTF J1828+2308 b is a confirmed gas-giant exoplanet 658 ly from Earth in the constellation Hercules, discovered in 2025 by Zwicky Transient Facility.

Transit: spotted by the tiny, repeating dip in its star’s light each time the planet crosses in front of it.

ZTF J1828+2308
host star
11.13 R⊕
radius
6,357 M⊕
mass · measured
2.7 hours
orbital period
avg temp
Human scale

ZTF J1828+2308 b is a giant ball of gas with no solid surface to stand on; you would simply sink into ever-thicker cloud. Bathing the cloud tops in icy blue-white light. A year passes in just 2.7 hours.

51.31 g
surface gravity (no solid surface · measured mass)
2.7 hours
one year, in Earth time
sun size, needs orbit
icy blue-white
midday sky tint
0.0×
how high you could jump vs Earth
rotation unknown
Calculate your exact weight on ZTF J1828+2308 b

What these mean: surface gravity · tidal locking · equilibrium temperature

If your children grew up herea playful thought experiment
NO GROUND: A DRIFTER, NOT A WALKER

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 51.3 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, and we have no temperature for this world, so its cloud-top acoustics cannot be modelled. In hydrogen-helium air sound races, so a voice would leap to a thin, almost cartoonish squeak.

The journey
Cosmic travel advisory
☆☆☆☆
Do not travel
  • !There is nowhere to land: no ground, no deck, only cloud that thickens into crushing pressure.

A playful read of ZTF J1828+2308 b’s measured and computed values, not a real advisory.

How long to get there · 658 ly away
Jet airliner
789 million years
dies en route1000-yr cryo: fails
Parker Solar Probethe fastest craft ever built
1.0 million years
dies en route1000-yr cryo: fails
Light speed
658 years
dies en route1000-yr cryo: survives
Warp 10
240 days
arrives thriving
Folding spacetimeinstant, plus 1 hr of paperwork
1 hour
arrives thriving
Size vs Earth
EarthZTF J1828+2308 b is 11× the width of Earth
Explore from here · roam the neighborhood

Zoom out: star → system → (soon) galaxy arm, host black hole, and a real image of the host galaxy.

Can you see it tonight? · observe
FAINT: LARGE TELESCOPE NEEDED
Host-star brightnessmag 18.0
ConstellationHercules
To see the host star10"+ (250 mm) telescope, dark sky
Gear bridge

Matched telescope & eyepiece recommendations are coming. Any product links will carry a clear affiliate disclosure.

Common questions

What is the gravity on ZTF J1828+2308 b?

ZTF J1828+2308 b is a gas giant with no solid surface to stand on. At its cloud tops, gravity pulls about 51 times as hard as Earth's.

How far is ZTF J1828+2308 b from Earth?

ZTF J1828+2308 b lies about 658 light-years from Earth.

How long would it take to get to ZTF J1828+2308 b?

At the speed of NASA's Parker Solar Probe, the fastest craft ever built, the journey would take about 1.0 million years.

How long is a year on ZTF J1828+2308 b?

ZTF J1828+2308 b completes one orbit of its star in 2.7 hours.

Illustration generated from ZTF J1828+2308 b's confirmed parameters, not a photograph.