Thea, a mars sized planet is theorized to have impacted Earth, causing Thea’s demise and perhaps a complete melt-down of the Earth. At the time, Earth was probably just a wasteland. It isn’t known exactly — in fact some of this is speculation based on the surviving evidence — for instance earth mantle debris on the Moon. An impact of Thea at approximately a 45 degree angle is thought to have brought about the final phases of Earth developments that eventually led to the forming of seas and the supercontinent Pangaea and the moon as well. Some of Thea is believed to be in the Asteroid Belt that orbits between Mars and Jupiter. Thea may have had an elliptical orbit that brought it close to the Earth and then far out and perhaps past Pluto towards the Oort Cloud; approximately very 3600 years.
“If We Had No Moon“ 44 minutes
OR “Do We Really Need the Moon?” 59 minutes http://www.youtube.com/watch?v=tMAC0ZZxZC4
- Ancient water in Moon rocks may actually be from proto-Earth (geek.com)
- Elliptical Orbits (geography.answers.com)
- Ask Ethan #2: Meet the Oort Cloud [Starts With A Bang] (scienceblogs.com)
- Forget Mars: Let’s get someone on the Moon – NASA veteran (go.theregister.com)