The conditions prevailing during the birth of the solar system resulted in Earth having only one Moon. At the time, the temperature near the Sun was very high indeed. So, all the material was gas, and could not form planets. A little farther from the Sun, there were metal flakes, and small pieces of rock which formed planetesimals. these flakes stuck together when they collided, and grew quickly in size. They became so big that collisions started to break them apart. Only the largest survived to become the terrestrial planets. Mercury, venus, Earth and Mars are terrestrial planets. The Moon may have come into being when a large planetesimal collided with the Earth.
the temperature outside the Martian orbit was low enough for tiny pieces of ice to survive in addition to flakes of metal and chunks of rock. So, there were more 'seeds' from which planets could materialize. Therefore, they grew quickly. They became large enough for their gravity to capture hydrogen and helium. The protoplanets captured so much gas that they became tiny solar systems. This meant that the heating, spinning, and flattering that happened round the Sun occurred here too. As a result, many satellites were formed round the Jovian planets, jupiter, saturn, Uranus and Neptune.