Labels:text | screenshot OCR: DEATH OF THE SUN Planetary IN ABOUT 5 BILLION years' time, most of nebula White dwarf the hydrogen in the Sun's core will have fused to form helium. Gravity will then make the core contract, which will increase its pressure and temperature. Hydrogen will start to "burn" in a shell around the core. The new energy generated by nuclear fusion in the shell will cause the Sun's outer layers to swell until the star becomes a huge red giant. Its outer layers will then drift off into space to form a planetary nebula. The core will remain behind as a fading white-dwarf star. DEATH OF A GIANT FACT FILE
