The findings, which are published in Nature, have important implications for our understanding of how Mars evolved. Billions of years ago, the planet may have had a thicker atmosphere that allowed liquid water to flow on the surface.
This thicker atmosphere may have been kept in place by a protective magnetic field, like the one Earth has. However, Mars lacks such a field today. Scientists have wondered whether the loss of this magnetic field led to the red planet losing its atmosphere to space over time and becoming the cold, dry desert it is today.
From residual magnetization in the crust, we think that Mars did once have a magnetic field, possibly from a core structure similar to that of Earth. However, scientists think that the core must have cooled and stopped moving at some point in its history.
A fairly well accepted theory is that the moon’s gravitational pull (tides) do a lot to churn earth’s molten core, that churning adds heat and the mantle is a fantastic insulator. So all together, the moon is probably what’s keeping our liquid core hot. (And in turn, the liquid core is probably what gives us our magnetic field. And the magnetic field is what keeps our atmosphere from blowing out into space. So that’s all pretty important)
That tidal churn effect may also be why we have plate tectonics, which by the way is absolutely necessary to support life as we know it. Without plate tectonics, heavier elements would all sink to the center of the earth, but those churning plates are always bringing a mix of elements back up to the surface. And without some of those heavy elements, carbon based life wouldn’t be possible. Also, technology wouldn’t really be possible either, because if you think those rare earth metals are rare now, just imagine if they weren’t found in earth’s crust at all.
I think we have a lot to thank the moon for, it’s probably the thing that does the most to make Earth a livable planet. Basically, if the Earth is special, the Moon is why.