Nasa discovers new solar system where life may have evolved on three planets

Astronomers have detected no less than seven Earth-sized worlds orbiting a cool dwarf star known as TRAPPIST-1.TRAPPIST-1 is an ultracool dwarf star that is approximately 8 per cent the mass of and 11 per cent the radius of our  Sun.No other star system known contains such a large number of Earth-sized and probably rocky planets.