What it’s like to stand here
K2-38 b
weight
3.08 g
sun
21.2× wider
sky
warm white

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

Rocky world

K2-38 b

K2-38 b is a confirmed rocky exoplanet 628 ly from Earth in the constellation Scorpius, discovered in 2016 by K2.

ESI 0.17628 lyDiscovered in 2016 by K2

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

K2-38
host star
1.54 R⊕
radius
7.30 M⊕
mass · measured
4.0 days
orbital period
993°C (1819°F)
avg temp
Human scale

Standing on K2-38 b, you would weigh about 208% more than you do on Earth. Its yellow, Sun-like star looks 21.2× wider than ours, bathing the surface in warm white 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 4.0 days, and at an estimated 993°C (1819°F) it is hot enough to melt rock.

3.08 g
your weight (measured mass)
4.0 days
one year, in Earth time
21.2× wider
how big its sun looks vs ours
warm white
midday sky tint
0.3×
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 K2-38 b
Earth Similarity Index0.17#4,281 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≈ 0.80xEARTH-RAISEDRAISED HERE
about 0.80x as tall as on Earth · a 5 ft 10 in adult could stand nearer 4 ft 8 in

Heavier than home, at 3.1 times Earth's gravity. A child would end up markedly shorter and powerfully built, about 0.80x as tall as on Earth: a 5 ft 10 in adult could stand nearer 4 ft 8 in. Bones, muscle, and heart would all grow heavier just to stand and move.

Bones
Thick and dense
More weight to bear forces the skeleton to grow denser and stronger all through childhood.
Heart
Large and powerful
Pushing blood upward against stronger gravity demands a bigger, harder-working heart.
Movement
Low and deliberate
A fall under this gravity lands hard, so movement stays slow, planted, and careful.

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 993°C (1819°F), sound would travel roughly 110% 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 ≈ 713 m/s · 2.10× 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
☆☆☆☆
Do not travel
  • !At about 993°C (1819°F), the daytime side glows: metals run liquid and any atmosphere is being torn away.
  • !Gravity is 3.1 times Earth's, so every movement is a strain and a fall could be fatal.
  • !Its star delivers about 426 times the sunlight Earth gets, a blinding, sterilizing glare.
  • !Earth-similarity index 0.17: this world has almost nothing in common with our own.
  • !Likely tidally locked: one hemisphere in endless day, the other in permanent night.

A playful read of K2-38 b’s measured and computed values, not a real advisory.

How long to get there · 628 ly away
Jet airliner
754 million years
dies en route1000-yr cryo: fails
Parker Solar Probethe fastest craft ever built
980,167 years
dies en route1000-yr cryo: fails
Light speed
628 years
dies en route1000-yr cryo: survives
Warp 10
229 days
arrives thriving
Folding spacetimeinstant, plus 1 hr of paperwork
1 hour
arrives thriving
Size vs Earth
EarthK2-38 b is 1.5× 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
SMALL TELESCOPE NEEDED
Host-star brightnessmag 11.3
ConstellationScorpius
To see the host star4-6" (100-150 mm) telescope
Gear bridge

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

Common questions

What is the gravity on K2-38 b?

K2-38 b's surface gravity is about 3.1 times Earth's.

How much would you weigh on K2-38 b?

Someone who weighs 150 pounds on Earth would weigh about 462 pounds on K2-38 b.

How far is K2-38 b from Earth?

K2-38 b lies about 628 light-years from Earth.

How long would it take to get to K2-38 b?

At the speed of NASA's Parker Solar Probe, the fastest craft ever built, the journey would take about 980,167 years.

How hot is K2-38 b?

K2-38 b's equilibrium temperature, the balance it reaches from its star's light alone before any greenhouse warming, is about 993°C (1819°F).

How long is a year on K2-38 b?

K2-38 b completes one orbit of its star in 4.0 days.

Illustration generated from K2-38 b's confirmed parameters, not a photograph.