Mystery surrounding Earth's core deepened by new study

The Earth's core, a solid iron ball, is losing heat faster than previously thought. This may indicate more decaying radioactive material or a faster solidification rate. Recent studies suggest the core, similar in size to Mars, rotates faster than the rest of the planet.

What is the composition of the Earth's core?

How does the heat loss of the Earth's core compare to previous estimates?

What implications does the faster solidification of the core have?

What is the size comparison of the Earth's core to Mars?

In what way is the core of the Earth rotating compared to the rest of the planet?