This discovery outside of our solar system is rare because the planets have the winning combination of being similar in size to Earth and being all temperate, meaning they could have water on their surfaces and potentially support life.
“This is the first time that so many planets of this kind are found around the same star,” said MichaÃ«l Gillon, lead study author and astronomer at the University of LiÃ¨ge in Belgium.
The seven exoplanets were
all found in tight formation around an ultracool dwarf star called TRAPPIST-1
. Estimates of their mass also indicate that they are rocky planets, rather than being gaseous like Jupiter. Three planets are in the habitable zone of the star, known as TRAPPIST-1e, f and g, and may even have oceans on the surface.
What we know