Scientists have discovered that moons could theoretically orbit all seven planets in the TRAPPIST-1 system despite the complex gravitational environment. Using computer simulations, a team of researchers have mapped stable zones where satellites could survive around each planet. They found that moons can remain stable up to about 40-45% of each planets sphere of gravitational influence. The neighbouring planets squeeze these stable zones slightly inward compared to isolated planets, but the effect is modest. Long term calculations suggest only tiny moons, roughly one ten millionth the mass of Earth, could survive the immense tidal forces.