They're not too hot, not too cold, and may provide just the right conditions for life to form.
Astronomers have found three Earth-sized worlds within the so-called habitable 'Goldilocks' zone of a nearby star.
The scientists believe at least one of these 'three bears' planets may be 'just right' for life to get going, giving the search for life elsewhere in the universe a significant boost.
The international team of astronomers that found the planets said they are orbiting an ultracool brown dwarf star about one-eighth the size of our sun called 2MASS J23062928-0502285.
Also known as Trappist-1, this dim and cool star fades slightly at regular intervals, indicating several objects are passing between the star and the Earth.
To read more, click here.