This is the inside of the Sun! The core is very hot- more than 15 MILLION Degrees Kelvin. (Kelvin is a measure of temperature, like Celcius or Farenheit. To give you a rough idea, 100 Celcius = 212 Farenheit = 373 Kelvin)
Radiation and energy from the Sun's interior is very intense, but the Earth only receives one billionth of the Sun's energy output!