The Earth's magnetic field is generated by the movement of liquid iron in its outer core. This creates an electric current that produces a magnetic field.
The Earth's outer core became liquid due to the intense heat and pressure in the early stages of its formation. As the Earth cooled, the outer core became molten and began to rotate, creating the current that generates the magnetic field.
The Earth's magnetic field is estimated to have first appeared around 3.5 billion years ago. This is based on evidence from ancient rocks that show magnetic alignment and the presence of minerals that only form in the presence of a magnetic field.
No, the Earth's magnetic field is constantly changing in strength and direction. In fact, it has reversed completely in polarity several times throughout history. The last reversal occurred around 780,000 years ago.
The Earth's magnetic field plays a crucial role in protecting the planet from harmful solar and cosmic radiation. It also helps animals navigate and is essential for the functioning of many technologies, such as compasses and satellites.