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exoplanet · orbiting ultra-cool red dwarf TRAPPIST-1

TRAPPIST-1e

One of seven Earth-sized planets around a tiny red star.

🚀 Travel there
TRAPPIST-1e — Drawn, not photographed.

What it is

Roughly Earth-sized planet in the habitable zone of the seven-planet TRAPPIST-1 system.

Exoplanet: A planet around another star. Every kind of thing there is →

Can you see it?

No. No telescope on Earth will show you this one; it is here to be understood, not seen. It is here because it is worth knowing about — and because leaving it out would make the sky look emptier than it is.

Worth knowing about TRAPPIST-1e

On the 100-meter-track scale model of the Milky Way, the TRAPPIST-1 system would be about 4 centimeters from the Sun — roughly the size of a walnut. Light takes 40 Earth years to get here from TRAPPIST-1e, so what you are looking at is TRAPPIST-1e as it was 40 Earth years ago.

What it is made of
Roughly Earth-sized, rocky, one of seven tightly-packed planets around an ultra-cool red dwarf, in the habitable zone.
How we know: The transit method: telescopes catch tiny repeating dips in starlight as each planet passes in front of the star.
What makes it worth knowing
Neighboring planets would appear bigger in the sky than our Moon does from Earth.
How did anyone measure the Earth in the first place?
The numbers
Across11 608 km
Distance from us40 light-years
Once round its orbit6.1 days

Where it sits

It belongs to TRAPPIST-1.

How anyone knows this

Nobody flew a tape measure out there. Every number on this page was worked out from the ground:

Next to it

TRAPPIST-1starNot observableProxima Centauri bexoplanetNot observable51 Pegasi bexoplanetNot observableThe Milky Wayspiral galaxyNaked eyeProxima CentauristarWith effortAlpha Centauri A & Bbinary star systemNaked eye
📖 How the Milky Way fits together

Then go outside

Not this one. But the sky over your head is full of ones you can see, and the Planetarium knows which.

🌙 Plan an evening outside🌌 Everything else in the sky