What influence does the core have on Earth

hmm......
no one really knows in what manner the core influences the Earth,but there have several predictions of what use the Earth's core might be...
firstly, the core is made mostly composed of iron and nickel and therefore it should be highly dense.(with the added effect of the compression, even more so)Since, iron and nickel are highly magnetized, the core happens to be the most plausible explanation for the source of the Earth's magnetic field, i.e., the orientation of the poles. In some times in the past, there have been several events when the Earth magnetic poles reversed, but the reason to it is still unknown.
Secondly, the core might be very instrumental especially the formation of Earth's gravitational field. The essence of any celestial body's gravitational field should have initiated from the core. For e.g., as the hot gases and debris swirl rapidly, centripetal force is generated. As the centripetal force became larger, the debris and the hot gases became concentrated into a pinpoint whereby it is densely lithified. This lithified chunk of rock is the Earth. But one may argue that as soon as there is no spinning then the centripetal force cease to work, and therefore the Earth disintegrates. However this does not happen because, in a very very densed environment such as the core, time is said to have stopped, and therefore, the centripetal force instead of collapsing, the force is trapped and it is known as gravitational force today.