- weight
- 4.65 g
- sun
- 10.0× wider
- sky
- amber-orange
Illustration computed from this world’s measured and derived values, not a photograph.
HD 21749 c
HD 21749 c is a confirmed rocky exoplanet 53.2 ly from Earth in the constellation Reticulum, discovered in 2019 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.
Standing on HD 21749 c, you would weigh about 365% more than you do on Earth. Its orange dwarf looks 10.0× wider than ours, bathing the surface in amber-orange 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 7.8 days, and at an estimated 428°C (802°F) it is furnace-hot.
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
Beyond about four times Earth's gravity, a growing child's skeleton could not carry its own weight. A human body simply could not develop here, even sheltered indoors. The shape below is only where the trend points before biology gives out: short, and impossibly dense.
- 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.
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 428°C (802°F), sound would travel roughly 56% 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.
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.
- !Furnace-hot at around 428°C (802°F), with no liquid water and no shade anywhere.
- !Gravity is 4.7 times Earth's, near the limit at which a person can stand or walk at all.
- !Its star delivers about 306 times the sunlight Earth gets, a blinding, sterilizing glare.
- !Likely tidally locked: one hemisphere in endless day, the other in permanent night.
A playful read of HD 21749 c’s measured and computed values, not a real advisory.
How long to get there · 53.2 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 HD 21749 c?
HD 21749 c's surface gravity is about 4.7 times Earth's.
How much would you weigh on HD 21749 c?
Someone who weighs 150 pounds on Earth would weigh about 698 pounds on HD 21749 c.
How far is HD 21749 c from Earth?
HD 21749 c lies about 53.2 light-years from Earth.
How long would it take to get to HD 21749 c?
At the speed of NASA's Parker Solar Probe, the fastest craft ever built, the journey would take about 83,016 years.
How hot is HD 21749 c?
HD 21749 c's equilibrium temperature, the balance it reaches from its star's light alone before any greenhouse warming, is about 428°C (802°F).
How long is a year on HD 21749 c?
HD 21749 c completes one orbit of its star in 7.8 days.
Illustration generated from HD 21749 c's confirmed parameters, not a photograph.