The Churning inside the Earth that makes it still a living planet

  The internal working inside the Earth's core is central to life on Earth. We have not explored the core of the Earth as much we have explored the universe. The core still remains a mystery but is vital for life on the Earth. It creates the Earth's magnetic field - assisting the annual mass migration including us to find our direction in life of course with a magnetic compass!! Also protecting life itself from the harmful cosmic and solar rays by creating a magnetic shield which has helped in the evolution of living organisms.

The Magnetosphere shielding Earth from harmful solar particles and cosmic radiation. (From: Climatepedia.org)

 Life on the surfaces of the Earth depends upon processes that happen inside the Earth's core, it has shaped the face of the Earth by creating habitats and environments for life to prosper. It is the churning/convection that takes place inside the earth that makes the crust (plates) move. 

An analogy of boiling water showing what happens inside the Earth.  

Plate Tectonic Boundaries driven by convection currents in the Mantle. (Source: Wikipedia)

  The day the churning stops it will have a disastrous consequences, there will be no mountains creation, no ocean basin formation and life will come to a standstill. Importantly we will be devoid of the protection of the Magnetosphere, the solar and cosmic radiation will strip off the Earth's atmosphere and hydrosphere just the same way it did for Mars and Venus. The interiors of the other terrestrial planets are similar to that of the Earth, although Mars has cooled so fast that its core is no longer molten making it a dead planet. The composition of the moon is similar to the crust of the Earth, and formerly had a molten core that has cooled and solidified. In general, small bodies cool more quickly than large ones because there is less material around their cores to trap the heat of their formation just like as you need a pullover to keep yourself warm in times of cold.

Comparison between the cores of Earth, Venus, Mars, Mercury and Moon.

  The core also gives rise to another important phenomenon that is the reversals in the poles, when there is a magnetic fluctuation happening inside the core. The core is an active place having storms and this being evident on the surface of the Earth with growing South Atlantic anomaly, which is moving westwards. All this shows that the Earth is a dynamic and a living planet in comparison to other planets in the solar system and it is important to appreciate and know that we are a small speck in the geological time scale.