What it’s like to stand here
SPECULOOS-3 b
weight
≈ 0.94 g
sun
16.7× wider
sky
dim red

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

Rocky world

SPECULOOS-3 b

SPECULOOS-3 b is a confirmed rocky exoplanet in the constellation Cygnus, discovered in 2024 by SPECULOOS Southern Observatory.

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

SPECULOOS-3
host star
0.98 R⊕
radius
0.89 M⊕
mass · estimated from radius
17.3 hours
orbital period
280°C (536°F)
avg temp
Human scale

Standing on SPECULOOS-3 b, you would weigh roughly about 6% less than you do on Earth. Its red dwarf looks 16.7× wider than ours, bathing the surface in dim red light. It is likely tidally locked, so that sun never moves in the sky: one hemisphere in endless day, the other in permanent night. A year passes in just 17.3 hours, and at an estimated 280°C (536°F) it is blistering.

≈ 0.94 g
your weight (mass estimated from size)
17.3 hours
one year, in Earth time
16.7× wider
how big its sun looks vs ours
dim red
midday sky tint
1.1×
how high you could jump vs Earth
likely
likely tidally locked: probably eternal day on one side, night on the other
Calculate your exact weight on SPECULOOS-3 b
Earth Similarity Index0.52#507 of 5,788 ranked worlds

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
EARTH HEIGHT≈ 1.0xEARTH-RAISEDRAISED HERE
much like Earth height

Gravity close to Earth's, at about 0.94 times. A child would grow up much as they would back home.

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 high and thin, almost cartoonish.

Assuming Earth-like air at this world's temperature of about 280°C (536°F), sound would travel roughly 39% faster than on Earth, so your voice would sound high and thin, almost cartoonish. The real atmosphere is unknown, so this is a best guess.

sound speed ≈ 471 m/s · 1.39× Earth · assumes Earth-like air

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.

The journey
Cosmic travel advisory
★★★☆☆
For seasoned travelers
  • !Blistering at about 280°C (536°F), far too hot for liquid water on the surface.
  • Surface gravity is close to Earth's, about 0.94 times, so you would move much as you do here.
  • !Likely tidally locked: one hemisphere in endless day, the other in permanent night.

A playful read of SPECULOOS-3 b’s measured and computed values, not a real advisory.

How long to get there · distance unknown away

Distance unknown for this world.

Size vs Earth
EarthSPECULOOS-3 b is about the size of Earth
Explore from here · roam the neighborhood
Host star
SPECULOOS-3
M6.5+/-0.5 · 1 planet
Explore →
Sibling worlds in this system

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.

Can you see it tonight? · observe
FAINT: LARGE TELESCOPE NEEDED
Host-star brightnessmag 17.8
ConstellationCygnus
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 SPECULOOS-3 b?

SPECULOOS-3 b's surface gravity is about 0.94 times Earth's, estimated from its size.

How much would you weigh on SPECULOOS-3 b?

Someone who weighs 150 pounds on Earth would weigh about 140 pounds on SPECULOOS-3 b.

How hot is SPECULOOS-3 b?

SPECULOOS-3 b's equilibrium temperature, the balance it reaches from its star's light alone before any greenhouse warming, is about 280°C (536°F).

How long is a year on SPECULOOS-3 b?

SPECULOOS-3 b completes one orbit of its star in 17.3 hours.

Illustration generated from SPECULOOS-3 b's confirmed parameters, not a photograph.