The corona is part of the Sun’s atmosphere. The Sun is not a solid nor a gas, but plasma—a superheated mix of electrically charged particles that stream along magnetic field lines. This plasma is tenuous and gaseous near the surface but gets denser toward the Sun’s core. The Sun’s core is about 27 million degrees Fahrenheit, and the temperature cools dramatically toward the outer layers of the Sun. The middle layer of the Sun, called the convection zone, is 3.5 million degrees Fahrenheit. At the very surface, the Sun is 10,000 degrees Fahrenheit. The Sun’s corona reaches temperatures up to several million degrees Fahrenheit, which is 200 to 500 times hotter than the solar surface below. Because the Sun produces its energy and heat in its center, scientists would typically expect that the Sun’s surface— closer to the core—would be hotter than the atmosphere above. The corona’s extremely high temperatures mean that there must be other mechanisms at work heating the solar atmosphere. We know that the energy is stored in the dynamic magnetic fields of the Sun, which constantly stir up the photosphere and release energy into the solar atmosphere. The precise details of how, when, and where that energy release occurs are still under investigation, The corona extends far out into space. From it comes the solar wind that travels through our solar system. The corona's temperature causes its particles to move at very high speeds. These speeds are so high that the particles can escape the Sun's gravity.