The Earth and the Moon.Then there was perhaps another planet called Theia that collided with Earth around four to five billion years ago, the Earth was halved in it’s size and the debris of the impact became the Moon.
It is said Theia was around the size of Mars and did not kill a planet but created a new one and an orbiting terrestrial satellite called the Moon.
She did not come from our Solar System but deep space, orbiting the sun for a short time before being flung in Earths direction at four kilometres an hour. Some say the planet gave us water, that when Earth and Theia merged, it was Theia that carried that life sustaining resource.
A life giver, a planet changer,named after the mother of a Goddess.Theia.