There are good reasons to think that Earth and Mars
originally formed a single planet outside the orbit of Jupiter. Then, about 4.47 billion years ago, Jupiter’s powerful gravitational field pulled this planet past the gas giant. As it neared Jupiter, tidal friction heated it to the melting point, and Jupiter tore Mars away from Earth, leaving the Pacific Basin and an array of evidence. Earth and Mars turned into comets that sped off into the inner solar system.