Earth, Moon, Mars and Venus

[Fallingstar1971]

Could Mars itself be the "Mars sized body" that impacted the Earth to form the moon, and the combined gravity effects of Earth and Venus catapulted it to its present orbit?

Star

 

[CalliArcale]

Could Mars itself be the "Mars sized body" that impacted the Earth to form the moon, and the combined gravity effects of Earth and Venus catapulted it to its present orbit?

Star

No. While Mars' orbit is more eccentric and more highly inclined than most of the major planets, it's still pretty regular as all things go. That suggests its been there pretty much since it formed.

Furthermore, I don't think Venus and Earth have enough gravitational influence to push it out to its current position. They could certainly affect it, but I think we'd be more likely to see a more eccentric orbit in that case.

Incidentally, the impactor would likely have merged with Earth and Moon in the process, assuming the theory is correct; any surviving pieces would be quite small. Mars is thus too big to be a suspect.

 

[Saiph]

As calli said, it's orbit is far to regular to be anything but a body formed in place. While a bit eccentric, it's still nearly circular.

 

[trumptor]

Could this ancient collision be part of the reason that the Earth still has a magnetic field, while Mars and Venus don't? If everything remelted from the impact, could the Earth, in a way be at an earlier stage in its cooling and that is part of the reason. And could the gravity from such a large moon also keep the Earth hotter and more active?

 

[baulten]

Could this ancient collision be part of the reason that the Earth still has a magnetic field, while Mars and Venus don't? If everything remelted from the impact, could the Earth, in a way be at an earlier stage in its cooling and that is part of the reason. And could the gravity from such a large moon also keep the Earth hotter and more active?

I think that's actually pretty much exactly it. The Earth's surface and upper mantle were likely remelted during the massive impact, plus the presence of a massive moon causes tidal fluctuations.