The central region of the Sun is called the core. It is very hot (about 15 million degrees) and very dense (about 14 times as dense as lead). It is here that all the energy which makes life on Earth possible is produced. Hydrogen is converted into Helium in a process called nuclear fusion and in the process a tiny amount of the Sun's mass is changed into a huge amount of energy.
How do scientists know what the temperature and density of the Sun's core is?