... Bad Astronomy . ... Bitesize Astronomy . ... even the brightest star won't last forever.' ... The pressure and heat are so enormous inside the star's core that hydrogen is fused into helium. ... A star like the Sun has enough hydrogen to keep its fusion fires going for billions of years, but a star like Rigel, a massive star in Orion, burns its hydrogen so fast it may run out in just a few million years. ... The problem is, at this point something bad happens: silicon fuses to iron. ...