NASA says they have discovered the first known system with 7 Earth-sized planets around a single star.
Three of those planets are in the habitable zone. That means conditions are right for liquid water.
They say this sets a new record for number of habitable-zone planets around a single star.
The star system TRAPPIST-1 is about 40 light-years from Earth. That’s about 235 trillion miles.
TRAPPIST stands for Transiting Planets and Planetesimals Small Telescope.
Scientists say they are likely to be rocky based on their densities.
More observations will help determine if they have water.
The star in this system is classified as an ultra-cool dwarf. It is a small star and the planets orbit very close to it.
Some of the planets have years that last less than a dozen days.
If you stood on one of the planets, another planet would look as close as the Moon to the Earth.
They say the planets may also be tidally locked. That means the same side of the planet is always facing the star.
One side of the planet would always be day – another side would always be night.