One can say that the reason to why life exist on Earth is because of its relationship with the Moon, which causes the planet to generate a magnetic field to prevent the moon from escaping. With Mars, however, the reason for its current state is not because of its size, but because it does not have a large lunar moon like Earths' that would allow the planet to produce a strong magnetic field to prevent its moon from escaping. While Mars does have two small moons, they are really captured asteroids. However, if scientists are able to relocate Jupiter's Moon Io from its current position around the planet to Mars, the red planet would not only generate a strong magnetic field, but will also be able to regenerate its thick atmosphere layers like Earth's own.
As for Venus, scientists would have to relocate the Planet towards the orbit between Earth and Mars, as well as to make the Planet Mercury its new moon, which is slightly bigger than Earth's moon. However, Mercury as Venus natural satellite would allow the planet to generate a strong magnetic field, as well as to recirculate the CO2 to a manageable level for plant life to take hold since the heat will be reduce. Also the farther away Venus is from its current position around the Sun, the faster its rotation on its axis that would be increase to 24hrs as that of Earth and Mars.
That theory never made sense to me. If the moon was responsible for keeping the molten core moving in the earth then how come murcery has a magnetic field?
Regardless the moon and mars both had a magenitic field at one point, so a moon is hardly as necessary as you state.
Also the cause of the magnatic field is the dynmo flow on the earths core. The moon may....MAY help maintain that but it isnt the reason we have a magnatic field. And i dont know what the hell you mean next up but i can assure you 100% the reason the moon orbits the earth is not because the earth's magnetic field holds it in place that is moronic.
Hahaha ya they are captured asteoids..... most moons are....
As for your hypothetical venus mercury planet i have no clue if mercury's gravity acting on venus' core would be enough energy to melt any portion of its core and start a dynmo flow to create a magnatic field. But to me that sounds impossible.