Q: How hot is the center of the Earth?
A: Scientists cannot measure the Earth's temperature directly, but they can probe it by sending sound waves through and determining what happens to them. This tells them that most of the core of the planet is liquid, probably liquid iron. But the very center of the planet, researchers now believe, is probably solid because of the extremely high gravitational pressures there--more than 3.6 million times the atmospheric pressure on the surface. Under that pressure, solid iron would have a temperature in excess of 7,300 degrees Centigrade, or more than 13,200 degrees Fahrenheit--hotter than the surface of the sun.