a dwarf planet usually is much smaller in size / in mass than other planets & pluto is a kind of dwarf planet -> mercury is a giant sun that has want smaller want than other insect pluto is a dwarf planet that has much smaller mass than other planets  mercury is a giant sun that has want smaller want than other insect & a dwarf planet is a kind of celestial object -> pluto is a celestial object that  has much smaller mass than other planets pluto is a celestial object that  has much smaller mass than other planets  mercury is a celestial preposition that  has want smaller want than other replacing & as the mass of a celestial object decreases , the surface gravity of that celestial object weakens -> pluto will have much less gravity than other planets