Earth's molten iron core creates a magnetic shield that stops solar winds from stripping away our atmosphere.

Earth's magnetic field is generated by the geodynamo process within the liquid outer core, which is composed primarily of molten iron and nickel. This layer sits approximately 2,890 kilometers beneath the surface and reaches temperatures between 4,000 and 5,000 degrees Celsius. The rotation of the Earth, combined with convection currents driven by heat escaping from the inner core, keeps this liquid metal in constant motion.As this conductive fluid moves, it creates electric currents that generate a massive magnetic field extending thousands of kilometers into space. This region is known as the magnetosphere. It serves as a vital barrier against the solar wind, a stream of plasma and high-energy particles ejected by the Sun at speeds of up to 800 kilometers per second. Without this protection, solar particles would collide directly with gas molecules in our upper atmosphere.Scientific evidence from NASA's MAVEN mission suggests that Mars lost its thick, water-rich atmosphere billions of years ago because its internal dynamo stopped. When the Martian core cooled and the magnetic field weakened, solar winds stripped away the planet's air. On Earth, the magnetosphere ensures that oxygen and nitrogen remain trapped by gravity rather than being ionized and swept away. This process has been crucial for maintaining liquid water and supporting life for over 3.5 billion years.